Table of Contents

## How do you find surface area with radius?

To calculate the surface area of a sphere, all you need to know is the sphere’s radius – or its diameter. A = 4 * π * r² where r is the radius.

## What will be the surface area of a sphere if its radius is doubled?

4 times

Hence, the surface area of the sphere will increase 4 times if the radius of that sphere is doubled.

**Why is the surface area of a sphere 4πr 2?**

The flat region will have a surface area equal to the area of a circle with radius r. The surface area of the curved portion of the hemisphere will equal one-half of the surface area of the uncut sphere, which we established to be 4πr2.

### What is the radius of a sphere?

A sphere’s radius is the length from the sphere’s center to any point on its surface. The radius is an identifying trait, and from it other measurements of the sphere can be calculated, including its circumference, surface area and volume.

### Why is the surface area of a sphere?

The Greek mathematician Archimedes discovered that the surface area of a sphere is the same as the lateral surface area of a cylinder having the same radius as the sphere and a height the length of the diameter of the sphere. The lateral surface area of the cylinder is 2πrh where h=2r .

**What is the total surface area of a hemisphere of radius r?**

Total surface area of a hemisphere is 3πr2 where ‘r’ is the radius of the hemisphere and ′π′ is equal to 22/7 or 3.14.

## How do you find the radius of a sphere?

How to Calculate the Radius of a Sphere?

- Radius = Diameter / 2. When the surface area is given, the formula used for the radius of a sphere is:
- Radius = ⎷[Surface Area / (4 π)] When the volume is given, the formula used for the radius of a sphere is:
- Radius = ³⎷[3 * Volume / (4 π)]

## What is a formula for a sphere?

The formula for the volume of a sphere is V = 4/3 πr³. See the formula used in an example where we are given the diameter of the sphere.