Calculating the Surface Area of a Sphere:
Surface Area (denoted 'SA') of a sphere with a known radius (denoted 'r') can be calculated using the formula below:
In plain english the surface area of a sphere can be calculated by squaring the radius, multiplying the result by PI, and finally multiplying by 4.
You can approximated PI using: 3.14159. If the number you are given for the radius does not have a lot of digits you may use a shorter approximation. If the radius you are given has a lot of digits then you may need to use a longer approximation.
Here is a step-by-step case that illustrates how to find the surface area of a sphere with a radius of 5 meters. We'll use 3.14 to approximate PI because the radius we're given only has one digit.
- V = 4(pi * r2
- = 4(3.14 * 52)
- = 4(3.14 * 25)
- = 4(314.16)
- = 314.16 meters square