Question

Some measures are given in the adjacent figure, find the area of ☐ABCD.

Answer 1

A(☐ABCD) = A(∆BAD) + A(∆BDC)

In ∆BAD, m∠BAD = 90°, l(AB) = 40m, l(AD) = 9m

A(∆BAD) = `1/2 xx "product of sides forming the right angle"`

= `1/2 xx l("AB") xx l("AD")`

= `1/2 xx 40 xx 9`

= 180 sq.m

In ∆BDC, l(BT) = 13m, l(CD) = 60m

A(∆BDC) = `1/2 "base" xx "height"`

= `1/2 xx l("CD") xx l("BT")`

= `1/2 xx 60 xx 13`

= 390 sq. m

A (☐ABCD) = A (∆BAD) + A (∆BDC)

= 180 + 390

= 570 sq. m

∴ The area of ☐ABCD is 570 sq. m.