Area and Circumference of a circle flashcardziz

Front

What is the formula for the circumference of a circle?

Back

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

Front

What is the relationship between diameter and radius?

Back

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

Front

What is the formula for the area of a circle?

Back

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

Front

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

Back

C = 2π(5) = 10π cm, approximately 31.4 cm.

Front

If the circumference of a circle is 62.8 cm, what is the diameter?

Back

Diameter d = C/π = 62.8/π = 20 cm.

Front

What is the diameter of a circle that has a circumference of 120π?

Back

Diameter d = 120 cm.

Front

If the diameter of a circle is 10 mm, what is the area?

Back

A = π(5)² = 25π mm², approximately 78.54 mm².

Front

What is the circumference of a circle with a radius of 3 cm?

Back

C = 2π(3) = 6π cm, approximately 18.84 cm.

Front

What is the radius of a circle with an area of 49π?

Back

Radius r = 7 cm.

Front

If the area of a circle is 100π, what is the radius?

Back

Radius r = 10 cm.