Question

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

Answer 1

the diagonal will be whole root of 15squared +8 squared that is root of (225+64)=root of 289=17
so the diagonal is 17 cm

Answer 2

Suppose that ABCD is a rect where AD is 15 cm nd CD is 8 cm.....AC is diagonal then diagonals of rect bist each other at right angle......hence we can apply pythagoras theorem in triangle ADC
(AC)×(AC)=(AD)×(AD)+(CD)×(CD)
= 15×15 + 8×8
= 225+64
=289
AC=17
Diagonal is 17 cm