Understanding Circles: Circumference and Area

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

• C = Pi * r^2

• C = Pi * d

• C = 2 * Pi * r

• C = Pi / d

What does 'squaring' a number mean?

• Adding it to itself

• Multiplying it by 2

• Multiplying it by itself

• Dividing it by itself

Why is squaring the radius important in finding the area of a circle?

• It simplifies the calculation

• It converts the radius to diameter

• It results in square units, matching area's dimensionality

• It gives the circle's diameter

What mistake do students commonly make when calculating the area of a circle?

• Multiplying the diameter instead of the radius

• Confusing radius with diameter

• Thinking r squared means 2 times r

• Forgetting to use Pi

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

• Diameter is half the radius

• Radius is half the diameter

• Diameter is double the radius

• Radius is double the diameter

How do you convert the diameter to the radius of a circle?

• Multiply by 2

• Divide by 2

• Double it

• Square it

How do you find the area of a circle?

• A = Pi * d^2

• A = Pi * r^2

• A = 2 * Pi * r

• A = Pi * d

What unit is used to measure the area of a circle?

• Circular units

• Cubic units

• Linear units

• Square units

What is the circumference of the Earth at the equator?

• Approx. 20,036 km

• Approx. 12,750 km

• Approx. 40,075 km

• Approx. 40,055 km

What is the total area of a pizza with a diameter of 24 inches?

• 452.16 square inches

• 226.08 square inches

• 904.32 square inches

• 678.24 square inches