Given:
In the fig. 1, m∠ BAD=90∘, AB=40 m, BT=13 m, DC=60 m, AD=9 m
Area of □ ABCD= area of △ BAD+ area of △ BDC
area of △ BAD =12× base× height
=12×40×9
=20×9=180 m2
First we need to calculate the area of △ BDC
Base DC =60 m and Height BT =13 m
Area (△ BDC)=12 base × height
Area(△ BDC) =12×60×13
Area(△ BDC)=30×13
Area(△ BDC)=390 sq.m.
Area of □ABCD= area of △ BAD + area of BDC
Area of □ABCD=180+390
Area of □ABCD=570 sq.m.
Hence, the area of the quadrilateral is 570 sq. m.