Question

The perimeter of a triangle is 90 cm.

The lengths of the sides of the triangle are in the ratios 3:5:7.
Work out the length of the longest side of the triangle.

Answer 1

Can you work out what one share is
If you don’t know comment

Answer 2

Let's call one ratio = x

So, the sides are 3x, 5x and 7x respectively.

Since the perimeter is 90 cm, the sum of 3 sides = 90 cm

-> 3x + 5x + 7x = 90 cm

-> 15x = 90cm
-> x = 6cm.

So, the 3 sides are 3x6, 5x6 and 7x6 -> 18,30 and 42.

Recheck : 18 + 30 + 42 = 90

18:30:42 = 3:5:7 (all divided by 6)