Question

Find the surface area of sphere of radius 4.2 cm.

Answer 1

Given: Radius r = 4.2 cm.

Step-wise calculation:

1. Surface area formula: S = 4πr².

2. r² = (4.2)²

= 17.64 cm²

3. 4r² = 4 × 17.64

= 70.56

4. S = 70.56 πcm² 

= 70.56 × 3.141592653589793... 

= 221.6707776... cm²

Surface area = 70.56 πcm² ≈ 221.67 cm².