What is the radius of a circle? Learn about the radius of a circle, including the formula for a radius, how to find and measure a radius, and examples of radii.
Example Problem 1 - How to Inscribe a Square in a Circle In the image below, the square is inscribed in the circle and the circle has a radius of 2 inches. Find the area and perimeter of the square.
The equation of a circle is the algebraic equality that describes it given its radius and its center. In this lesson, we saw two forms of the equation: the standard form and the center-radius form.
What is the diameter of a circle? Learn the formula, and see examples of how to find the diameter of a circle using the radius, circumference, or area.
Learn how to draw a circle with a given radius or diameter and see examples that walk through sample problems step-by-step for you to improve your geometry knowledge and skills.
Learn how to inscribe an equilateral triangle in a circle, and see examples that walk through sample problems step-by-step for you to improve your math knowledge and skills.
Given the circumference, C, of a circle, the area can be found by dividing the circumference by 2, and multiplying that result by the radius. That is, A = (C / 2)r.
A circle is a two-dimensional shape in which all points on the circumference (perimeter) are equidistant from the center. That fixed distance is called the radius.
