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.

Work out the lengths of each side; do so by adding the ratio components together (3+4+5).The components add to 12; we can now find the value of a single unit of the ratio, by dividing 72 by 12.72/12 is 6; each part of the ratio needs to be multiplied by 6 to get the final side length.3 x 6 = 18cm4 x 6 = 24cm5 x 6 = 30cmYou can check this is correct by adding up all the new lengths; 18 +24+30 = 72, so this is correct!Now, if you draw the right angled triangle and label it, use the area = (base x height)/2 formula to work out the area.The diagonal side of a triangle is always the longest, so that length is 30cm . l . 24cm l . 30cm Therefore, the area of the triangle is (18x24)/2, the same as (18x12). The area is 216cm2 l . l________ . 18cm

LF
Answered by Lorissa F. Maths tutor

3060 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

There are 10 boys and 20 girls in a class. The mean mark for the class is 60, the mean mark for the girls is 54. Work out the mean mark for the boys.


Find the highest common factor (HCF) of 12 and 18.


Solve 5x-2=3x+11


Show that (sqrt(3) + sqrt(75))^{2} = 108


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