Question

Find the area of a parallelogram ABCD in which AB = 28 cm, BC = 26 cm and diagonal AC = 30 cm.

Answer 1

In △ ABC

Take a = 26cm, b = 30cm and c = 28cm

So we get

We know that the diagonal divides the parallelogram into two equal area

So the area of parallelogram ABCD = Area of △ ABC + Area of △ ACD

It can be written as

Area of parallelogram ABCD = 2(Area of △ ABC)

By substituting the values

Area of parallelogram ABCD = 2 (336)

By multiplication

Area of parallelogram ABCD = 672 cm²

Therefore, the area of parallelogram ABCD is 672 cm².

Comments

Thankyou

Answer 2

We know that diagonal of parallelogram bisect it into two equal parts
by heron's formula
S=(28+26+30)/2= 42
area∆=√42(42-28)(42-26)(42-30)
√42×14×16×12=14×3×2×4=336

area of parallelogram=2(area∆)=2(336)=672