More Lessons for High School Regents Exam

Math Worksheets

High School Math based on the topics required for the Regents Exam conducted by NYSED.

How to Calculate the Area of a Circle

The area of circles is derived by dividing a circle into an infinite number of wedges formed by radii drawn from the center. When these wedges are rearranged, they form a rectangle whose height is the radius of the circle and whose base length is half of the circumference of the circle.

This video will first show how to identify what fraction of the circle is occupied by the sector and then how to multiply that fraction by the entire area of the circle.

A sector in a circle is the region bound by two radii and the circle. Since it is a fractional part of the circle, the area of any sector is found by multiplying the area of the circle, pi × r

This video explains the definition of a sector and how to find the sector area of a circle. It shows how to solve 2 example problems, one for finding the sector of a circle and the other to find the radius of a circle with a given sector area.

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