Circumference & Area of Circles

Front

What is the formula for the circumference of a circle?

Back

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

Front

What is the formula for the area of a circle?

Back

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

Front

If the radius of a circle is 5 ft, what is the diameter?

Back

The diameter (d) is 10 ft, calculated as d = 2r.

Front

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

Back

π is commonly approximated as 3.14.

Front

What is the relationship between radius and diameter?

Back

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

Front

What is the circumference of a circle with a radius of 7 cm?

Back

The circumference is 43.96 cm, calculated as C = 2π(7) using π ≈ 3.14.

Front

What is the area of a circle with a radius of 3 m?

Back

The area is 28.26 m², calculated as A = π(3)² using π ≈ 3.14.

Front

What do we call the distance around a circle?

Back

The distance around a circle is called the circumference.

Front

If the diameter of a circle is 12 in, what is the radius?

Back

The radius is 6 in, calculated as r = d/2.

Front

What is the area of a circle with a diameter of 10 ft?

Back

The area is 78.5 ft², calculated as A = π(5)² using π ≈ 3.14.