Circumference and Area of a Circle

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2 × π × radius or Circumference = π × diameter.

Front

What is the value of π (pi) commonly approximated as?

Back

π is commonly approximated as 3.14.

Front

If the radius of a circle is 9 meters, what is the circumference?

Back

56.52 meters.

Front

What is the radius of a circle?

Back

The radius is the distance from the center of the circle to any point on its circumference.

Front

What is the diameter of a circle?

Back

The diameter is twice the length of the radius, or the distance across the circle through its center.

Front

How do you find the area of a circle?

Back

Area = π × radius².

Front

If the diameter of a circle is 2.5 inches, what is the radius?

Back

The radius is 1.25 inches.

Front

What is the area of a circle with a radius of 5 inches?

Back

Area = π × (5 inches)² = 78.5 square inches.

Front

What does it mean to find the circumference of a circle?

Back

Finding the circumference means calculating the total distance around the circle.

Front

If a playground needs to be fenced, what measurement do you need?

Back

You need to find the circumference of the circle.