Exploring Area and Circumference of Circles

This video tutorial reviews the concepts of area and circumference of circles. It covers the parts of a circle, including the circumference, diameter, and radius, and explains how to calculate the radius from the diameter. The tutorial introduces formula charts for geometry and provides examples of calculating circumference and area using given dimensions. Students are encouraged to practice these calculations through provided problems, reinforcing their understanding of the material.

What is the radius of a circle if its diameter is 10 units?

• 2.5 units

• 20 units

• 5 units

• 10 units

How do you find the radius from the diameter of a circle?

• Square the diameter

• Divide the diameter by 2

• Multiply the diameter by 2

• Multiply the diameter by π

Using the formula C = πd, what is the circumference of a circle with a diameter of 14 units?

• 43.96 units

• 44 units

• 28 units

• 88 units

If the radius of a circle is 7 units, what is its circumference using C = 2πr?

• 14 units

• 14π units

• 44 units

• 22 units

What formula is used to calculate the circumference of a circle when the radius is known?

• C = πd

• A = πr^2

• C = 2πr

• A = πd^2

A circle's diameter is 20 units. What is its circumference?

• 20π units

• 40 units

• 62.8 units

• 10π units

What is the area of a circle with a radius of 4 units?

• 50.24 square units

• 16π square units

• 12.56 square units

• 25.12 square units

A circle has a diameter of 16 units. What is its area?

• 256π square units

• 128π square units

• 64π square units

• 200.96 square units

If a circle has a radius of 9 units, what is its area?

• 81π square units

• 36π square units

• 18π square units

• 72π square units

What is the area of a circle with a diameter of 10 units?

• 100π square units

• 50π square units

• 25π square units

• 78.5 square units