Question

ABCD is a parallelogram with side AB=12 cm. Its diagonal AC and BD are of lengths 20 cm and 16 cm respectively. Find the area of parallelogram ABCD. 

I tried, 

Area of parallelogram=1/2*product of diagonals =1/2*20*16 

But, this is not matching the answer at the back of the book.

Answer 1

Let the diagonal AC = d₁ = 20 cm.

Let the diagonal BD = d₂ = 16 cm.

Area of the Parallelogram is 1/2 d₁d₂.

= 1/2 * 20 * 16

= 160 square units.

Therefore area of the parallelogram ABCD is 160 square units.