Finding the Area of Circles and Semicircles

This video tutorial explains how to calculate the area of a circle using the formula A = πr². It covers examples with both radius and diameter, emphasizing the importance of using the correct units and order of operations. The tutorial also includes practice problems for calculating the area of semicircles, highlighting the need to divide by two. The video encourages viewers to pause and solve problems independently before checking their solutions.

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

• Area = Pi * radius

• Area = Pi / radius^2

• Area = 2 * Pi * radius

• Area = Pi * radius^2

If a circle has a radius of 5 cm, what is its area using Pi = 3.14?

• 62.8 cm^2

• 157 cm^2

• 31.4 cm^2

• 78.5 cm^2

How do you find the radius if you're given the diameter of the circle?

• Divide the diameter by Pi

• Multiply the diameter by 2

• Divide the diameter by 2

• Multiply the diameter by Pi

What is the area of a circle with a diameter of 14 cm using Pi = 3.14?

• 615.44 cm^2

• 76.93 cm^2

• 153.86 cm^2

• 307.72 cm^2

What is the first step in calculating the area of a semicircle?

• Square the radius

• Multiply the diameter by Pi

• Divide the diameter by 2 to find the radius

• Multiply the radius by 2

What is the area of a semicircle with a diameter of 10 cm using Pi = 3.14?

• 19.625 cm^2

• 157 cm^2

• 78.5 cm^2

• 39.25 cm^2

If the diameter of a semicircle is 9 feet, what is the radius?

• 2.25 feet

• 4.5 feet

• 9 feet

• 18 feet

What is the area of a semicircle with a radius of 4.5 feet using Pi = 3.14?

• 31.79 square feet

• 63.585 square feet

• 15.895 square feet

• 127.17 square feet

How do you calculate the area of a semicircle?

• Pi * radius^2

• 2 * Pi * radius

• (Pi * radius^2) / 2

• Pi * diameter^2

What is the area of a semicircle with a radius of 13 inches using Pi = 3.14?

• 132.665 square inches

• 530.66 square inches

• 1061.32 square inches

• 265.33 square inches