Question

Find the radius of a circle whose circumference is
30.8 cm and 44 cm
​

Answer 1

Answer:

12.25

Step-by-step explanation:

The formula is 2πr

30.8 when we convert decimals in to by form then it will be 308/10

308/19 circumference

308/10=2(22/7)r

12.25

Answer 2

(i) 30.8 cm

Solution

Circumference of a circle = 2π × radius

➡ 30.8 cm = 2π × radius

➡ 30.8 cm/2 = π × radius

➡ 15.4 cm = π × radius

➡ 15.4 cm = 22/7 × radius

➡ 15.4 cm × 7/22 = radius

➡ 154 cm/10 × 7/22 = radius

➡ 7/10 cm × 7 = radius

➡ 49 cm/10 = radius

➡ 4.9 cm = radius

4.9 cm is the radius of the circle with circumference 30.8 cm.

(ii) 44 cm

Solution

Circumference of a circle = 2π × radius

➡ 44 cm = 2π × radius

➡ 44 cm/2 = π × radius

➡ 22 cm = π × radius

➡ 22 cm = 22/7 × radius

➡ 22 cm × 7/22 = radius

➡ 7 cm = radius

7 cm is the radius of the circle with circumference 44 cm.

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More relations:

• Diameter of a circle = 2 × radius
• Radius of a circle = Diameter/2
• Area of a circle = πr²