Understanding the Area of a Circle

What is the area of a circle?

• The distance around the circle

• The distance across the circle

• The amount of space inside the circle

• The length of the circle's boundary

Which formula is used to calculate the area of a circle using its radius?

• A = 2πr

• A = πr²

• A = πd

• A = 2πd

What is the approximate value of π used in calculations?

• 3.75

• 3.50

• 3.14

• 3.00

If the radius of a circle is 5 decimeters, what is the area?

• 78.5 square decimeters

• 100 square decimeters

• 25 square decimeters

• 50 square decimeters

How do you calculate the square of a radius?

• Multiply the radius by π

• Multiply the radius by 2

• Multiply the radius by itself

• Divide the radius by 2

What is the area of a circle with a radius of 9 inches?

• 200 square inches

• 254.30 square inches

• 81 square inches

• 100 square inches

What changes in the formula when using the diameter instead of the radius?

• Use the diameter directly

• Use the square of the diameter

• Use half of the diameter

• Use twice the diameter

If the diameter of a circle is 12 inches, what is the area?

• 113.04 square inches

• 36 square inches

• 72 square inches

• 144 square inches

How do you find half of the diameter?

• Add 2 to the diameter

• Divide the diameter by 2

• Multiply the diameter by 2

• Subtract 2 from the diameter

What is the formula for the area of a circle when the diameter is given?

• A = πd

• A = πd²

• A = 2πd

• A = π(d/2)²