Area of a circle

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

What is the formula for the area of a circle?

Back

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

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.

Front

If the radius of a circle is 9 inches, what is the area in terms of π?

Back

The area is 81π in².

Front

What is the relationship between radius and diameter?

Back

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

Front

How do you find the area of a circle with a radius of 10 cm?

Back

Using the formula A = πr², the area is 100π cm².

Front

What does π (pi) represent in circle calculations?

Back

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

Front

What is the circumference of a circle?

Back

The circumference is the distance around the circle, calculated using the formula C = 2πr.

Front

If a circle has an area of 36π cm², what is its radius?

Back

The radius is 6 cm, since A = πr² implies r = √(A/π).

Front

What is the area of a circle with a diameter of 8 cm?

Back

The area is 16π cm², since the radius is 4 cm.