Surface Area of a Sphere Calculator
This Surface Area of a Sphere Calculator helps you find the total outer area of a sphere when the radius is known. It uses the formula SA = 4πr², where r is the radius and the answer is written in square units. First square the radius, then multiply by 4π to get the surface area. It is a simple way to check answers, understand the sphere surface area formula, and practise basic geometry step by step.
Radius is labeled r.
Step-by-step method
- Identify what is given.
- Write the formula.
- Substitute the value and calculate the surface area.
Formula:
Example 1: r = 5
Step 1 - Identify what is given.
In this problem: The given radius is r = 5.
Step 2 - Write the formula.
In this problem: Use the sphere surface area formula: SA = 4πr².
Step 3 - Substitute the value and calculate the surface area.
In this problem: Substitute r = 5: SA = 4π × 5² = 314.15926536.
Final answer: SA = 314.15926536
Example 2: r = 3.5
Step 1 - Identify what is given.
In this problem: The given radius is r = 3.5.
Step 2 - Write the formula.
In this problem: Use the sphere surface area formula: SA = 4πr².
Step 3 - Substitute the value and calculate the surface area.
In this problem: Substitute r = 3.5: SA = 4π × 3.5² = 153.93804003.
Final answer: SA = 153.93804003
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