Question

Write the proper values in the blanks in the following table:

S. No.	Radius	Diameter	Circumference	Area
(1)	42 cm	........	........	........
(2)	........	9.8 m	........	........
(3)	........	........	44 m	........
(4)	........	........	........	616 sq cm

Answer 1

(1) Radius of the circle is 42 cm.
Diameter of a circle = 2r = 2 × 42 cm = 84 cm
Circumference = πd = π × 84 = 264 cm
Area = πr²
= π × 42 cm × 42 cm
= 5544 sq cm $\left(\mathrm{Taking}\mathrm{\pi }=\frac{22}{7}\right)$
∴ Diameter of the circle = 84 cm
Circumference = 264 cm
And area of the circle is 5544 sq cm.

(2) Diameter of the circle is 9.8 m.
Radius of a circle = $\frac{d}{2}$ = $\frac{9.8}{2}$ = 4.9 m
Circumference = πd = π × 9.8 = 30.8 m
Area = πr²
= π × 4.9 m × 4.9 m
= 75.46 sq m $\left(\mathrm{Taking}\mathrm{\pi }=\frac{22}{7}\right)$
∴ Radius of the circle = 4.9 m
Circumference = 30.8 m
And area of the circle is 75.46 sq m.

(3) Circumference of the circle is 44 m.
Circumference = πd = 44m
⇒ d = $\frac{44\times 7}{22}$ = 14 m
r = $\frac{d}{2}$ = 7 m
Area = πr²
= π × 7 m × 7 m
= 154 sq m $\left(\mathrm{Taking}\mathrm{\pi }=\frac{22}{7}\right)$
∴ Radius of the circle = 7 m
Diameter of the circle = 14 m
And area of the circle is 154 sq m.

(4) Area of the circle is 616 sq cm.
Area = πr²
⇒ 616 = πr²
⇒ r = 14 cm
Diameter = 2 × r = 28 cm
⇒ Circumference = πd = $\frac{22}{7}$ × 28 cm
Circumference = 88 cm
∴ Radius of the circle = 14 cm
Diameter of the circle = 28 cm
Circumference = 88 cm

S. No.	Radius	Diameter	Circumference	Area
(1)	42 cm	84 cm	264 cm	5544 sq cm
(2)	4.9 m	9.8 m	30.8 m	75.46 sq m
(3)	7 m	14 m	44 m	154 sq m
(4)	14 cm	28 cm	88 cm	616 sq cm