NZ Herald
  • Home
  • Latest news
  • Herald NOW
  • Video
  • New Zealand
  • Sport
  • World
  • Business
  • Entertainment
  • Podcasts
  • Quizzes
  • Opinion
  • Lifestyle
  • Travel
  • Viva
  • Weather

Subscriptions

  • Herald Premium
  • Viva Premium
  • The Listener
  • BusinessDesk

Sections

  • Latest news
  • New Zealand
    • All New Zealand
    • Crime
    • Politics
    • Education
    • Open Justice
    • Scam Update
  • Herald NOW
  • On The Up
  • World
    • All World
    • Australia
    • Asia
    • UK
    • United States
    • Middle East
    • Europe
    • Pacific
  • Business
    • All Business
    • MarketsSharesCurrencyCommoditiesStock TakesCrypto
    • Markets with Madison
    • Media Insider
    • Business analysis
    • Personal financeKiwiSaverInterest ratesTaxInvestment
    • EconomyInflationGDPOfficial cash rateEmployment
    • Small business
    • Business reportsMood of the BoardroomProject AucklandSustainable business and financeCapital markets reportAgribusiness reportInfrastructure reportDynamic business
    • Deloitte Top 200 Awards
    • CompaniesAged CareAgribusinessAirlinesBanking and financeConstructionEnergyFreight and logisticsHealthcareManufacturingMedia and MarketingRetailTelecommunicationsTourism
  • Opinion
    • All Opinion
    • Analysis
    • Editorials
    • Business analysis
    • Premium opinion
    • Letters to the editor
  • Politics
  • Sport
    • All Sport
    • OlympicsParalympics
    • RugbySuper RugbyNPCAll BlacksBlack FernsRugby sevensSchool rugby
    • CricketBlack CapsWhite Ferns
    • Racing
    • NetballSilver Ferns
    • LeagueWarriorsNRL
    • FootballWellington PhoenixAuckland FCAll WhitesFootball FernsEnglish Premier League
    • GolfNZ Open
    • MotorsportFormula 1
    • Boxing
    • UFC
    • BasketballNBABreakersTall BlacksTall Ferns
    • Tennis
    • Cycling
    • Athletics
    • SailingAmerica's CupSailGP
    • Rowing
  • Lifestyle
    • All Lifestyle
    • Viva - Food, fashion & beauty
    • Society Insider
    • Royals
    • Sex & relationships
    • Food & drinkRecipesRecipe collectionsRestaurant reviewsRestaurant bookings
    • Health & wellbeing
    • Fashion & beauty
    • Pets & animals
    • The Selection - Shop the trendsShop fashionShop beautyShop entertainmentShop giftsShop home & living
    • Milford's Investing Place
  • Entertainment
    • All Entertainment
    • TV
    • MoviesMovie reviews
    • MusicMusic reviews
    • BooksBook reviews
    • Culture
    • ReviewsBook reviewsMovie reviewsMusic reviewsRestaurant reviews
  • Travel
    • All Travel
    • News
    • New ZealandNorthlandAucklandWellingtonCanterburyOtago / QueenstownNelson-TasmanBest NZ beaches
    • International travelAustraliaPacific IslandsEuropeUKUSAAfricaAsia
    • Rail holidays
    • Cruise holidays
    • Ski holidays
    • Luxury travel
    • Adventure travel
  • Kāhu Māori news
  • Environment
    • All Environment
    • Our Green Future
  • Talanoa Pacific news
  • Property
    • All Property
    • Property Insider
    • Interest rates tracker
    • Residential property listings
    • Commercial property listings
  • Health
  • Technology
    • All Technology
    • AI
    • Social media
  • Rural
    • All Rural
    • Dairy farming
    • Sheep & beef farming
    • Horticulture
    • Animal health
    • Rural business
    • Rural life
    • Rural technology
    • Opinion
    • Audio & podcasts
  • Weather forecasts
    • All Weather forecasts
    • Kaitaia
    • Whangārei
    • Dargaville
    • Auckland
    • Thames
    • Tauranga
    • Hamilton
    • Whakatāne
    • Rotorua
    • Tokoroa
    • Te Kuiti
    • Taumaranui
    • Taupō
    • Gisborne
    • New Plymouth
    • Napier
    • Hastings
    • Dannevirke
    • Whanganui
    • Palmerston North
    • Levin
    • Paraparaumu
    • Masterton
    • Wellington
    • Motueka
    • Nelson
    • Blenheim
    • Westport
    • Reefton
    • Kaikōura
    • Greymouth
    • Hokitika
    • Christchurch
    • Ashburton
    • Timaru
    • Wānaka
    • Oamaru
    • Queenstown
    • Dunedin
    • Gore
    • Invercargill
  • Meet the journalists
  • Promotions & competitions
  • OneRoof property listings
  • Driven car news

Puzzles & Quizzes

  • Puzzles
    • All Puzzles
    • Sudoku
    • Code Cracker
    • Crosswords
    • Cryptic crossword
    • Wordsearch
  • Quizzes
    • All Quizzes
    • Morning quiz
    • Afternoon quiz
    • Sports quiz

Regions

  • Northland
    • All Northland
    • Far North
    • Kaitaia
    • Kerikeri
    • Kaikohe
    • Bay of Islands
    • Whangarei
    • Dargaville
    • Kaipara
    • Mangawhai
  • Auckland
  • Waikato
    • All Waikato
    • Hamilton
    • Coromandel & Hauraki
    • Matamata & Piako
    • Cambridge
    • Te Awamutu
    • Tokoroa & South Waikato
    • Taupō & Tūrangi
  • Bay of Plenty
    • All Bay of Plenty
    • Katikati
    • Tauranga
    • Mount Maunganui
    • Pāpāmoa
    • Te Puke
    • Whakatāne
  • Rotorua
  • Hawke's Bay
    • All Hawke's Bay
    • Napier
    • Hastings
    • Havelock North
    • Central Hawke's Bay
    • Wairoa
  • Taranaki
    • All Taranaki
    • Stratford
    • New Plymouth
    • Hāwera
  • Manawatū - Whanganui
    • All Manawatū - Whanganui
    • Whanganui
    • Palmerston North
    • Manawatū
    • Tararua
    • Horowhenua
  • Wellington
    • All Wellington
    • Kapiti
    • Wairarapa
    • Upper Hutt
    • Lower Hutt
  • Nelson & Tasman
    • All Nelson & Tasman
    • Motueka
    • Nelson
    • Tasman
  • Marlborough
  • West Coast
  • Canterbury
    • All Canterbury
    • Kaikōura
    • Christchurch
    • Ashburton
    • Timaru
  • Otago
    • All Otago
    • Oamaru
    • Dunedin
    • Balclutha
    • Alexandra
    • Queenstown
    • Wanaka
  • Southland
    • All Southland
    • Invercargill
    • Gore
    • Stewart Island
  • Gisborne

Media

  • Video
    • All Video
    • NZ news video
    • Herald NOW
    • Business news video
    • Politics news video
    • Sport video
    • World news video
    • Lifestyle video
    • Entertainment video
    • Travel video
    • Markets with Madison
    • Kea Kids news
  • Podcasts
    • All Podcasts
    • The Front Page
    • On the Tiles
    • Ask me Anything
    • The Little Things
  • Cartoons
  • Photo galleries
  • Today's Paper - E-editions
  • Photo sales
  • Classifieds

NZME Network

  • Advertise with NZME
  • OneRoof
  • Driven Car Guide
  • BusinessDesk
  • Newstalk ZB
  • Sunlive
  • ZM
  • The Hits
  • Coast
  • Radio Hauraki
  • The Alternative Commentary Collective
  • Gold
  • Flava
  • iHeart Radio
  • Hokonui
  • Radio Wanaka
  • iHeartCountry New Zealand
  • Restaurant Hub
  • NZME Events

SubscribeSign In

Advertisement
Advertise with NZME.
Home / Lifestyle

Can you figure out this tricky maths problem?

Daily Mail
27 Apr, 2018 03:32 AM3 mins to read

Subscribe to listen

Access to Herald Premium articles require a Premium subscription. Subscribe now to listen.
Already a subscriber?  Sign in here

Listening to articles is free for open-access content—explore other articles or learn more about text-to-speech.
‌
Save

    Share this article

The key to getting the correct answer - which is a third - is working out that the height of the triangle is two thirds the height of the square. Photo / via Twitter

The key to getting the correct answer - which is a third - is working out that the height of the triangle is two thirds the height of the square. Photo / via Twitter

A tricky maths problem is sweeping the internet - with many offering lengthy explanations on how to solve the question.

Sharing the puzzle online, mathematician Ed Southall, from the University of Huddersfield, posted an image of a pink triangle inside a square, along with the deceivingly simple question: "What fraction is shaded?"

Dozens of social media users shared their attempts at solving the difficult problem online, with some admitting they had been left scratching their heads.

However, education charity CEO David Weston has managed to offer a simple explanation of the correct answer.

What fraction is shaded? pic.twitter.com/f4kAjoX4C7

— Ed Southall (@edsouthall) April 23, 2018
Advertisement
Advertise with NZME.
Advertisement
Advertise with NZME.

The key to getting the correct answer - which is a third - is working out that the height of the triangle is two thirds the height of the square.

David explained: "Pink triangle and little triangle have all the same angles: they're 'similar'.

"Base of pink is twice base of little [triangle]. So height of pink is also twice height of little.

"So height of pink is 2/3 of whole square."

Advertisement
Advertise with NZME.

Simplest answer I can think of:
- Pink triangle and little triangle have all the same angles: they're 'similar'
- Base of pink is twice base of little
- So height of pink is also twice height of little
- So height of pink is 2/3 of whole square
- So area = half x 1 x 2/3 = 1/3 https://t.co/7Hxz3R4VtH

— David Weston FCCT (@informed_edu) April 24, 2018

The final stage of solving the problem involves using the formula for working out the area of a triangle - which is half x base x height.

As the height is 2/3 of the whole square, you can take the base to be equal to 1 when using the formula.

Therefore, as David explains, the area is half x 1 x two thirds.

This means the area of the triangle a third of the area of the whole square.

Dozens of other social media users have been sharing their solutions to the trick puzzle online, with one explaining: 'The intersection height is the key'.

Another added: "My instinct says it's 1/3... but I'll have to work on the explanation!"

pic.twitter.com/JBRI2hm97T

— Retweets en Maths (@MathsRetweets) April 23, 2018

pic.twitter.com/fIit5to24O

— Andy Currie (@andy_brfc) April 23, 2018

Pink triangle has area 4 times that of the small, similar triangle. The small triangle takes up half of one sixth of the full shape (see image). So the pink area is 4 times half of one sixth which makes two times one sixth which is one third. pic.twitter.com/VzaxYtFpSn

— Mr Allan (@mrallanmaths) April 23, 2018

the intersection height is the key - i think the answer is 1/3 pic.twitter.com/NUYwmh0k6G

— Chris Dlugosz (@cubosh) April 24, 2018

So height of pink triangle = 2/3 length of square, hence

area(rectangle under black dotted line) = 2/3 area(square)
= 2 area(pink triangle)

The answer is 1/3! pic.twitter.com/GcoWpjFBKK

— Dr Smoky Furby (@DrSmokyFurby) April 24, 2018
Save

    Share this article

Latest from Lifestyle

Premium
Lifestyle

I gave up pasta for a month – this is what it does for your health

Lifestyle

NZ bodycare founder Tanné Snowden: 'Living with endometriosis doesn't mean you're broken'

Royals

'Life is precious': Prince Harry open to reconciliation with royal family


Sponsored

Sponsored: Why heat pumps make winter cheaper

Advertisement
Advertise with NZME.

Latest from Lifestyle

Premium
Premium
I gave up pasta for a month – this is what it does for your health
Lifestyle

I gave up pasta for a month – this is what it does for your health

Telegraph: It’s cheap and easy, but if you’re in midlife, it might be time for a rethink.

15 Jul 06:00 AM
NZ bodycare founder Tanné Snowden: 'Living with endometriosis doesn't mean you're broken'
Lifestyle

NZ bodycare founder Tanné Snowden: 'Living with endometriosis doesn't mean you're broken'

15 Jul 02:00 AM
'Life is precious': Prince Harry open to reconciliation with royal family
Royals

'Life is precious': Prince Harry open to reconciliation with royal family

15 Jul 01:53 AM


Sponsored: Why heat pumps make winter cheaper
Sponsored

Sponsored: Why heat pumps make winter cheaper

01 Jul 04:58 PM
NZ Herald
  • About NZ Herald
  • Meet the journalists
  • Newsletters
  • Classifieds
  • Help & support
  • Contact us
  • House rules
  • Privacy Policy
  • Terms of use
  • Competition terms & conditions
  • Our use of AI
Subscriber Services
  • NZ Herald e-editions
  • Daily puzzles & quizzes
  • Manage your digital subscription
  • Manage your print subscription
  • Subscribe to the NZ Herald newspaper
  • Subscribe to Herald Premium
  • Gift a subscription
  • Subscriber FAQs
  • Subscription terms & conditions
  • Promotions and subscriber benefits
NZME Network
  • The New Zealand Herald
  • The Northland Age
  • The Northern Advocate
  • Waikato Herald
  • Bay of Plenty Times
  • Rotorua Daily Post
  • Hawke's Bay Today
  • Whanganui Chronicle
  • Viva
  • NZ Listener
  • Newstalk ZB
  • BusinessDesk
  • OneRoof
  • Driven Car Guide
  • iHeart Radio
  • Restaurant Hub
NZME
  • About NZME
  • NZME careers
  • Advertise with NZME
  • Digital self-service advertising
  • Book your classified ad
  • Photo sales
  • NZME Events
  • © Copyright 2025 NZME Publishing Limited
TOP