Question

8. A paper is in the form of ABCD in which AB=9m, BC=40m.
i) Find the length of AC,
i) Calculate the cost of fencing the given figure if it is charged Rs.2 per
metre.
iii) Find the area occupied by the shaded region.
А
D
132
B
C​

Answer 1

Answer:

Diagonal AC passes through the centre of the circle.

∴ AC is the diameter.

Now, area of rectangle ABCD= AB×AC

= 28×21

= 588cm

2

In △ABC

AC

2

=AB

2

+CB

2

=28

2

+21

2

=784+441

=1225

⇒AC

2

=

1225

⇒AC=35 cm

∴ radius =

2

AC

=

2

35

= 17.5

Area of the circle = πr

2

=

7

22

×(17.5)

2

= 962.5cm

2

Area of the shaded region = Area of the circle − Area of rectangle ABCD

= 962.5−588cm

2

= 374.5cm

2