Question

find the length of the diagonal of a rectangle whose sides are 15 cm and 8 cm

Answer 1

sides of the rectangle = 15cm and 8 cm
diagonal = x
x square =15 square + 8 square
(by using Pythagorean theorem)
x square = 225+ 64
x = root of 289
x = 17

Answer 2

Length of the diagonal = x                    

Sides of rectangle or Length of the Legs of Right angled triangle  = 15cm and 8cm

By using pythagorean theorem (a²+b²=c²)..

∴ 15²+8²=x²

225+64=289=x²

x=√289=17

Length of the diagonal = 17cm

HOPE IT HELPS..