Question

Find the perimeter of the rectangle whose length is 12cm and a diagonal is 15cm.

Answer 1

Given :-

Length => 12 cm

Diagonal => 15 cm

To find :-

Perimeter of the rectangle

Solution :-

Using Pythagoras theorem, we have:

(H)² = (P)² + (B)²

(15)² = (12)² + (B)²

225 = 144 + (8)²

(B)² = 225 – 144

(B)² = 81

B = √81

B = 9

Now,

Perimeter of a rectangle => 2 × (Length + Breadth)

Perimeter of the rectangle => 2 × (12 + 9) cm

Perimeter of the rectangle => 2 × 21 cm

Perimeter of the rectangle => 42 cm

Hence, the perimeter of the rectangle is 42 cm.