Virtual Nerd: How Do You Find the Area of a Circle if You Know the Radius?

If you have the diameter of a circle, you can use it to find the area of that circle. Watch this tutorial to learn how it's done. [4:01]

You can use the formula for the area of a circle to find the radius. This tutorial shows you how to use that formula and the given value for the area to find the radius. [3:28]

How do you find the area of a sector of a circle? Use the formula of course. Then all you have to do is plug in the given values and do the math. Make sure you are following the rules of order of operation. The instructor will walk you...

Learn how to use the formula for area to solve a problem about a rectangle. The demonstrator shows how to plug in the known values of a rectangle, and then how to use the formula for area to solve for the variable in question.

The teachers uses a diagram to set up her initial equation to reflect the changes being made to a garden plot. She has a good explanation of how she got her equation. Then she works through the steps to solve the equation.

Trapezoids can be tricky. Break down the process of finding the area of a trapezoid with this video! Viewers are given information about the area formula and shown exactly how to plug in information, solve, and simplify. This is a...

Trapezoids can be tricky! Break down the process of finding the area of a trapezoid with an engaging math video. Learners explore area formula and shown exactly how to plug in information, solve, and simplify. 

There are two formulas that can be used to find the circumference of a circle. Choose the appropriate formula depending on the given value in the problem. After selecting the correct formula, solve the problem using 3.14 as an estimation...

Take a look at this tutorial to see how to break down a composite figure into simpler figures, then discover how to find the area of each of those individual figures to find the area of the entire composite figure. [4:18]

Go back to the basics and review how to find the square root of a perfect square. This video will walk you through the process and provide examples. [1:59]