Circumference and Area of Circles

Front

What is the definition of a circle?

Back

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

Front

What is the formula for the circumference of a circle?

Back

The circumference (C) of a circle is calculated using the formula C = 2πr, where r is the radius.

Tags

CCSS.7.G.B.4

Front

What is the formula for the area of a circle?

Back

The area (A) of a circle is calculated using the formula A = πr², where r is the radius.

Tags

CCSS.7.G.B.4

Front

What is the relationship between diameter and radius?

Back

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

Tags

CCSS.7.G.B.4

Front

What is the diameter of a circle?

Back

The diameter is the distance across the circle through the center.

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

If the radius of a circle is 5 cm, what is the circumference?

Back

C = 2π(5) = 10π cm (approximately 31.42 cm).

Tags

CCSS.7.G.B.4

Front

If the radius of a circle is 3 cm, what is the area?

Back

A = π(3)² = 9π cm² (approximately 28.27 cm²).

Tags

CCSS.7.G.B.4

Front

What is π (pi)?

Back

π (pi) is a mathematical constant approximately equal to 3.14, representing the ratio of the circumference of a circle to its diameter.

Tags

CCSS.HSG.GMD.A.1

Front

How do you find the radius if you know the diameter?

Back

To find the radius, divide the diameter by 2: r = d/2.

Tags

CCSS.7.G.B.4