Circumference of a Circle

Front

What is the formula for the circumference of a circle?

Back

C = 2πr, where C is the circumference and r is the radius.

Tags

CCSS.7.G.B.4

Front

If the radius of a circle is 10 cm, what is its circumference?

Back

C = 2π(10) = 62.83 cm.

Tags

CCSS.7.G.B.4

Front

What does the term 'circumference' refer to?

Back

The circumference is the distance around the circle.

Front

If the diameter of a circle is 20 m, what is the circumference?

Back

C = πd = π(20) ≈ 62.83 m.

Tags

CCSS.7.G.B.4

Front

What is the relationship between diameter and radius?

Back

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

Tags

CCSS.7.G.B.4

Front

How do you convert circumference from meters to kilometers?

Back

Divide the circumference in meters by 1000.

Tags

CCSS.2.MD.A.2

Front

What is the circumference of a circle with a radius of 5 ft?

Back

C = 2π(5) ≈ 31.42 ft.

Tags

CCSS.7.G.B.4

Front

If a circle has a circumference of 31.4 m, what is its radius?

Back

r = C/(2π) = 31.4/(2π) ≈ 5 m.

Tags

CCSS.7.G.B.4

Front

What is π (pi)?

Back

π 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 circumference if you only know the area of the circle?

Back

First, find the radius from the area (A = πr²), then use C = 2πr.

Tags

CCSS.7.G.B.4