Ch8 Circles & Composite Figures

Front

What is a circle?

Back

A circle is a shape consisting of all points in a plane that are a fixed distance (radius) from a center point.

Front

What is the diameter of a circle?

Back

The diameter is the distance across the circle through the center, equal to twice the radius.

Front

What is a radius?

Back

A radius is a line segment from the center of the circle to any point on its circumference.

Front

What is the formula for the circumference of a circle?

Back

The formula for the circumference is C = 2πr, where r is the radius.

Front

What is the formula for the area of a circle?

Back

The formula for the area is A = πr², where r is the radius.

Front

What is a composite figure?

Back

A composite figure is a shape that is made up of two or more simple shapes.

Front

How do you find the area of a composite figure?

Back

To find the area of a composite figure, calculate the area of each simple shape and then sum them up.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the length of the radius (d = 2r).

Front

What is the circumference of a circle with a radius of 8 inches?

Back

C = 2π(8) = 16π inches.

Front

What is the area of a circle with a diameter of 12 inches?

Back

First, find the radius: r = 12/2 = 6 inches. Then, A = π(6)² = 36π square inches.