Circles - Area and Circumference

Front

What is the formula for the area of a circle?

Back

A = πr², where A is the area and r is the radius.

Tags

CCSS.7.G.B.4

Front

What is the formula for the circumference of a circle?

Back

C = 2πr or C = πd, where C is the circumference, r is the radius, and d is the diameter.

Tags

CCSS.7.G.B.4

Front

What is the radius of a circle?

Back

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

Front

What is the diameter of a circle?

Back

The diameter is a line segment that passes through the center of the circle and connects two points on its circumference. It is twice the length of the radius.

Tags

CCSS.HSG.C.A.2

Front

If the radius of a circle is 7 cm, what is the area?

Back

A = π(7)² = 49π cm² (approximately 153.94 cm²).

Tags

CCSS.7.G.B.4

Front

If the diameter of a circle is 20 cm, what is the radius?

Back

Radius = diameter/2 = 20 cm / 2 = 10 cm.

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

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

Back

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

Tags

CCSS.7.G.B.4

Front

What does π (pi) represent in circle calculations?

Back

π is a 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 convert diameter to circumference?

Back

Use the formula C = πd.

Tags

CCSS.7.G.B.4