Question

please answers this question fast maths class 7 don't post unless answer I want full explanation OK don't short answer don't spam it ​

Answer 1

1. Given :

Radius of circular sheet = 5 cm

Radius of circular sheet removed = 3 cm

To Find :

Area of the remaining sheet.

Solution:

Area of remaining sheet = Area of circular sheet- Area of circular sheet removed

Area of a circle =πr²

Area of remaining sheet = ( $\frac {22}{7}$ × 5 × 5 ) - ( $\frac {22}{7}$ × 3 × 3)

= 78.57 - 28.28

= 50.29 cm ²

2. Given:

Area of circle = 616 cm ²

To find:

Circumference of circle

Solution:

Area of circle = πr²

616 = $\frac {22}{7}$ × r²

r² = 616 × $\frac {7}{22}$

r² = 28 × 7

r² = 196

r = √196

r = 14 cm

Circumference of circle = 2πr

= 2 × $\frac {22}{7}$ × 14

= 88 cm

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