The perimeter of a right-angled triangle is 72 cm. The lengths of its sides are in the ratio 3 : 4 : 5. Work out the area of the triangle.

We know the perimiter is split into the proportions 3:4:5 therefore by adding 3+4+5 we can work out what fraction of 72cm each side is.Thus 3/(3+4+5) = 3/12 = 1/4 is the fraction of 72 that belongs to the shortest side. This means the shorest side has lenght of 1/4 * 72 = 18cm.We can repeat this to work out the lenght of the other two sides giving the middle sized side to have lenght 4/12 * 72 = 1/3 * 72 = 24cm.And the longest side lenght 5/12 * 72 = 30cm.
We can now draw and label a sketch of the triangle.As it is a right anlged triangle we can use the formular Area = 1/2 * Base * Height. Which gives 24 * 18 * 1/2 = 12 * 18 = 10 * 18 + 2 * 18 = 216cm2

SD
Answered by Sefton d. Maths tutor

10065 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

A shop trying to sell a laptop reduces its price by 7% at the very end of each week, from an initial price of £600. If you have £365 to spend, how many weeks must you wait until you can buy the laptop?


Test


Solve the Simultaneous equation: 4x+y=25, x-3y=13


A fridge of height 2m and width 0.8m is tilted in a delivery van so that one edge rests on the edge of a table and another touches the ceiling, as shown in the diagram. The total height of the inside of the van is 1.5m. Find the height of the table.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences