Question

Find the surface area of a sphere of radius 7 cm.

Hint:

The surface area of a sphere is always given by $4\pi r^2$. Don’t forget to square the radius and multiply by 4.

Answer 1

Step 1: Formula for surface area of a sphere.
The formula for the surface area of a sphere is: \[ \text{Surface area} = 4\pi r^2 \]
Step 2: Substitute the given values.
Given that $r = 7$ cm and $\pi = \dfrac{22}{7}$, we have: \[ \text{Surface area} = 4 \times \dfrac{22}{7} \times (7)^2 \]
Step 3: Simplify the expression.
\[ \text{Surface area} = 4 \times \dfrac{22}{7} \times 49 \]
\[ \text{Surface area} = 4 \times 22 \times 7 \]
\[ \text{Surface area} = 616 \, \text{sq. cm.} \]
Step 4: Conclusion.
Therefore, the surface area of the sphere is: \[ \boxed{616 \, \text{sq. cm.}} \]