Exploring Area and Circumference of Circles

What term is used to describe the perimeter of a circle?

• Circumference

• Area

• Diameter

• Radius

What is the formula for the area of a circle?

• pi / r^2

• 2 * r

• pi * r^2

• 2 * pi * r

If the radius of a circle is 20 units, what is its area using pi as 3.14?

• 400 units squared

• 628 units squared

• 1256 units squared

• 314 units squared

What does the 'r' symbolize in the formula for the area of a circle?

• Pi

• Radius

• Circumference

• Diameter

What is the formula for the circumference of a circle?

• pi / r

• 2 * pi * r

• pi * r^2

• 2 * r

If a circle's diameter is 18 units, what is its radius?

• 4.5 units

• 36 units

• 18 units

• 9 units

Using a diameter of 18 units, what is the circumference of the circle using pi as 3.14?

• 84.78 units

• 28.26 units

• 113.04 units

• 56.52 units

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

• The radius is twice the diameter.

• The diameter is half the radius.

• There is no relationship.

• The diameter is twice the radius.

How do you calculate the area of a shaded quarter of a circle with a radius of 3 units using pi as 3.14?

• 28.26 units squared

• 3.14 units squared

• 7.07 units squared

• 14.13 units squared

In calculating the area of a shape that combines a square and a circle, what mathematical operation is used?

• Subtraction

• Multiplication

• Division

• Addition