Question

Find the length of the diagnoal of a rectangle whose sides are 12cm and 5cm

Answer 1

5 ,12,13 - Pythagoras triplet
13 will be the answer
diagonal²= 12²+5²= 144+25=169
diagonal=√169= 13 cm

Answer 2

The diagonal cuts the rectangle into two equal halves. The halves will be in the shape of triangles. We know that two sides of the triangle have lengths of 12cm and 5cm.

To find the length of the diagonal side, we use the Pythagoras theorem: c² (our diagonal) = a² + b² which is the same as c = √(a² + b²)

Diagonal length

= √(12² + 5²)

= √(144 + 25)

= √169

= 13cm