Question

find the shaded area correct to 1 d.p. ( use 3.14 for π)

Answer 1

Given
Dia of big circle =10cm
Dia of small circle =8cm

(pi=3.14)

So we can solve this problem in two way

1st

Area of Shaded region = area of big circle =area of small circle

Area of big circle = pi R²


R=10/2 =5cm (r=d/2)


Area= 3.14x5²

=314/100 x25

=314/4=157/2 cm²


=78.5cm²


Area of small circle = pi r²

r=8/2=4


Area =3.14 x 4²

Area=3.14x16

=50.24cm²



Area of Shaded region = 78.5-50.24

=28. 26cm²


2nd way or short way


Area of Shaded region = pi(R²-r²)

=3.14(5²-4²)

=3.14(25-16)

=3.14x9

=28.26cm²


This is ur ans hope it will help you in case of any doubt comment below

Answer 2

area of shaded region =π(R²-r²)
=3.14(5²-4²)
=3.14×9=28.26cm²