Circles

What is the definition of a circle?

• A circle is a straight line with no endpoints.

• A circle is a polygon with four sides.

• A circle is a three-dimensional shape with height, width, and depth.

• A circle is a closed curve in which all points are equidistant from the center point.

What is the formula to calculate the circumference of a circle?

• 2 * pi * radius

• radius * radius

• 2 * radius

• pi * radius

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

• 8 cm

• 10 cm

• 15 cm

• 12 cm

What is the relationship between the radius and diameter of a circle?

• The diameter of a circle is equal to the length of its radius.

• The diameter of a circle is three times the length of its radius.

• The diameter of a circle is half the length of its radius.

• The diameter of a circle is twice the length of its radius.

What is the formula to calculate the area of a circle?

• A = 2πr

• A = πd

• A = πr^2

• A = r^2

If the radius of a circle is 8 cm, what is its circumference?

• 64π cm

• 32 cm

• 16π cm

• 4π cm

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

• 3 cm

• 9 cm

• 15 cm

• 6 cm

If the circumference of a circle is 30 cm, what is its diameter?

• 15 cm

• 10 cm

• 4.7746482927568605

• 20 cm

If the area of a circle is 64 square cm, what is its radius?

• 2 cm

• 6 cm

• 8 cm

• 4 cm

If the circumference of a circle is 18 cm, what is its radius?

• 2.87 cm

• 9 cm

• 6 cm

• 3.14 cm