Question

the answer in my asnwersheet is a. 70.56 sq. m
b. 154 sq cm. c. 81.44 sq. cm ​

Answer 1

Answer:

1.

firstly let's find out the area of rectangle

AREA OF RECTANGLE = LENGTH × WIDTH

LENGTH= 15m

WIDTH = 8.4m given....

now the area will be

15×8.4 m = 126sq.m

now the area of the semi circle

AREA OF SEMI CIRCLE = 1/2× 22/7 ×RADIUS Sq.

( RADIUS = diameter/2

diameter = 8.4m now RADIUS will be 8.4/2 = 4.2)

[ will multiple 2 coz there are 2 semi circle ]

now

area =2×1/2×22/7×(4.2) Sq

=2×1/2×22/7×17.64

=22/7× 17.64

=22×2.52

=55.44sq.m

NOW

AREA OF SHADED REGION = AREA OF RECTANGLE–AREA OF 2 SEMI CIRCLE

=(126–55.44)Sq.m

=70.56 sq.m answer

2.

AREA OF SHADED REGION = 4× AREA OF SECTOR

(multiplying 4 coz there are 4 sectors)

= 4× 90/360×22/7×(7)Sq.

=4×1/4×22/7×49

=22×7

=154sq.m answer

3.

firstly let's find out the area of triangle

AREA OF TRIANGLE = HEIGHT × BASE/2

(HEIGHT = 18

BASE =20. ....given)

=18×20/2

=180sq.cm

now,

AREA OF CIRCLE = 22/7×(RADIUS) Sq.

(RADIUS = 5.6cm given.. )

=22/7×(5.6)Sq.

= 81.44sq.cm approx.