It All Adds Up- July 18, 2016

Italladdsup

Hi there! For today’s math lesson, I wanted to explain a deeper and more difficult concept involving finding the area of circles. It involves a shape that looks something like this:

 CircleAreaProblem.jpg

For this shape, our goal is to find the area of the shaded portion. As you can see, this shape consists of both a circle and a square. To solve this problem, we need to first find the area of both the square and the circle. Then, we would subtract the area of the circle from the area of the square. Use this diagram to help you out:

CircleAreaProblem.jpg

Since we know we can find the area of a square through length x width, and that all sides of a square are equal, we can easily find that the square has an area of 144 square inches. For the circle, we first substitute 3.14 for pi. Then, since we know that the diameter of the circle is 12 inches, the radius (half of the diameter) is six inches. Then, we square six inches and complete the multiplication problem. Then, we subtract the area of the circle from the area of the square to get an area of 30.96 sq. inches for the shaded area.

Now that you know how to find the area of a shaded portion, test your skills with this problem. Check your answers on July 23!

CircleAreaProblem.jpg

Thanks for reading!

Gabe

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