Table of Contents

## How do you find the radius if you have the circumference?

To find the radius from the circumference of a circle, you have to do the following:

- Divide the circumference by π, or 3.14 for an estimation. The result is the circle’s diameter.
- Divide the diameter by 2.
- There you go, you found the circle’s radius.

## What is the radius if it is half of the diameter?

Just remember to divide the diameter by two to get the radius. If you were asked to find the radius instead of the diameter, you would simply divide 7 feet by 2 because the radius is one-half the measure of the diameter. The radius of the circle is 3.5 feet.

**What is half of the circumference?**

Half of the circumference of the circle = (1/2) × Circumference of circle = (1/2) × 2πr = πr = π(d/2) Length of diameter = d = 2r. The circumference of the semicircle in terms of the radius is P = C = 2πR/2 = πR. In terms of diameter, the circumference of the semicircle is P = C = π(d/2) + d.

### How do you find the radius of a half circle?

Calculating the Radius of a Semicircle With a Known Circumference

- C = 2 π r C = 2\pi r C=2πr.
- S C = 0.5 × 2 π r SC = 0.5 × 2 \pi r SC=0. 5×2πr.
- S C = π r SC = \pi r SC=πr.

### What is the formula of a half circle?

In the case of a circle, the formula for area, A, is A = pi * r^2, where r is the circle’s radius. Since we know that a semicircle is half of a circle, we can simply divide that equation by two to calculate the area of a semicircle. So, the formula for the area of a semicircle is A = pi * r^2/2.

**How do you find the half diameter of a circle?**

What is the Diameter of a Circle Formula When Radius of a Circle is Known? If the radius of a circle is given in ‘r’ units then it is easy to determine the diameter of the circle formula. With the definition of radius, we know that it is half of the diameter hence, the diameter formula = 2r.