Circumference and Area of Circles

This video tutorial covers the calculation of circumference for half and quarter circles. It explains the formulas used for these calculations, including the addition of the diameter in the case of half circles. The video provides examples of calculating circumference and area, and demonstrates how to work backwards from a given circumference to find the radius. The lesson concludes with a summary and preparation for further practice.

What is the main focus of this video tutorial?

• Calculating the area of full circles

• Exploring the volume of spheres

• Learning about the diameter of circles

• Understanding the circumference of half and quarter circles

Which formula is used to calculate the circumference of a half circle?

• C = πr + 2r

• C = 2πr

• C = 2πr/2 + 2r

• C = πd

In the example calculation, what is the radius of the half circle?

• 5 meters

• 7.2 meters

• 10 meters

• 3.6 meters

What additional component is added to the formula for the circumference of a quarter circle?

• The area

• Two radii

• The radius

• The diameter

In the quarter circle example, what is the radius used for calculation?

• 12 feet

• 4 centimeters

• 7 meters

• 5 inches

What was the mistake corrected in the recalculation example?

• Miscalculated area

• Wrong radius used

• Incorrect value of π

• Incorrect formula applied

When working backwards, what is the first step to find the radius from a given circumference?

• Simplify the equation

• Divide the circumference by π

• Calculate the area

• Use the formula C = 2πr

In the example of working backwards for a half circle, what is the calculated radius?

• 11 inches

• 6 yards

• 12 miles

• 5 centimeters

What is the formula used to find the area of a quarter circle?

• Area = 2πr

• Area = πr²

• Area = πr²/4

• Area = πr²/2

In the example of working backwards for a quarter circle, what is the final calculated area?

• 94.985 inches squared

• 226.08 miles squared

• 78.5 centimeters squared

• 56.502 yards squared