Question

Find the length of the circumference of a circle whose diameter is 7 cm.

Answer 1

Given: Diameter d = 7 cm. (Use C = πd, equivalently C = 2πr)

Step-wise calculation:

1. Use formula:

C = πd

2. Substitute d = 7 cm:

C = π × 7

= 7π cm

3. Numeric approximations:

With π = 3.14159265

C = 7 × 3.14159265

= 21.9911486 cm   ...(Using π = `22/7` gives C = 22.0 cm.)

Circumference = 7π cm ≈ 21.99 cm (≈ 22.0 cm if using π = `22/7`).