Question

a rectangle has an area of 21 and a perimeter of 20. what is the length of its diagonal?

Answer 1

This is a fun Question!! :D

Okay so if area = 21
Then
l * b = 21
peremeter = 20 = 2*(l+b)
Or (l+b) = 10

So we got 2 equations..

(l+b) = 10
lb = 21

HINT: Use (l+b)^2 = l^2 + b^2 + 2lb

Diagonal is found by pythagorus theorem!! :D