Question

the circumference of a circle is 63cm.find its radius ,diameter and area​

Answer 1

Step-by-step explanation:

Given :

The circumference of a circle is 63 cm

To find :

• radius
• diameter
• area of the circle

Solution :

Let r be the radius and d be the diameter of the circle.

The circumference of the circle = 2πr

 63 = 2 × 22/7 × r

 63 = 44/7 × r

  r = 63 × 7/44

  r = 441/44

  r ≈ 10.023 cm

∴ The radius of the circle is approximately 10.023 cm

The diameter of the circle is double the radius.

d = 2r

d = 2 × 10.023

d = 20.046 cm

∴ The diameter of the circle is 20.046 cm

Area of the circle = πr²

 $\tt A= \dfrac{22}{7} \times \bigg( \dfrac{441}{44} \bigg)^2 \\\\ \tt A=\dfrac{22}{7} \times \dfrac{441}{44} \times \dfrac{441}{44} \\\\ \tt A=\dfrac{22}{7} \times \dfrac{7 \times 63}{22 \times 2} \times \dfrac{441}{44} \\\\ \tt A=\dfrac{63}{2} \times \dfrac{441}{44} \\\\ \tt A=\dfrac{27783}{88} \\\\ \tt A \approx 315.72 \ cm^2$

∴ The area of the circle is 315.72 cm²