Question

area covered by a circle window is 616m^2

(a)find radius (b)circumference of the window


​

Answer 1

Given,

πr

2

=616

r

2

=

22

616×7

r

2

=28×7

r=14

Therefore, Circumference = 2πr=2×

7

22

×14=88 cm

Answer 2

Given

• Area of the circle = 616m².

⠀

To find

• Radius of the circle.
• Circumference of the circle.

⠀

Solution

• As we can see that, in (a) part we need to find the radius. For this, we use the formula of area of a circle.

⠀

☆ Area = πr²

⠀

→ Area = 616

⠀

→ πr² = 616

⠀

→ 22/7 × r² = 616

⠀

→ 22r² = 616 × 7

⠀

→ 22r² = 4312

⠀

→ r² = 4312/22

⠀

→ r² = 196

⠀

→ r = √196

⠀

→ r = 14m

⠀

• We have radius of the circle and need to find the circumference of the circle.

⠀

☆ Circumference = 2πr

⠀

→ Circumference = 2 × 22/7 × 14

→ Circumference = 2 × 22 × 2

→ Circumference = 88m

⠀

Hence,

• Radius of Circle = 14m
• Circumference of circle = 88m