Understanding the Area of a Circle

This video tutorial covers the concept of the area of a circle, explaining how it is the space occupied by a circle and measured in square units. The formula for calculating the area, A = πr², is detailed, with π approximated as 3.14. The video includes examples of finding the area using given radii and diameters, and explains the order of operations. It also covers semicircle area calculations and applies these concepts to real-world problems, such as determining the amount of material needed to cover circular spaces.

What is the area of a circle primarily concerned with?

• The distance around the circle

• The space inside the circle

• The circumference of the circle

• The diameter of the circle

Which of the following is used as the value of pi in the area formula?

• 3.1416

• 3.14

• 3.142

• 3.14159

If the diameter of a circle is given, how do you find the radius?

• Subtract 2 from the diameter

• Add 2 to the diameter

• Divide the diameter by 2

• Multiply the diameter by 2

In the formula for the area of a circle, what does the exponent in R squared signify?

• Multiply the radius by 3

• Multiply the radius by itself

• Divide the radius by 2

• Add the radius to itself

What is the area of a circle with a radius of 1.2 meters, rounded to the nearest hundredth?

• 5.44 square meters

• 6.28 square meters

• 4.52 square meters

• 3.14 square meters

How do you calculate the area of a semicircle?

• Multiply the area of a full circle by 2

• Subtract the radius from the area of a full circle

• Divide the area of a full circle by 2

• Add the radius to the area of a full circle

If a semicircle has a diameter of 5, what is its radius?

• 2.5

• 10

• 1.25

• 5

Jane has a circular garden with a diameter of 16 feet. How many bags of fertilizer are needed if one bag covers 30 square feet?

• 8 bags

• 6 bags

• 7 bags

• 5 bags

Bob needs to buy a cover for his pool with a diameter of 18 feet. How much will it cost if the cover is 75 cents per square foot?

• $150.00

• $190.76

• $200.00

• $250.34

What is the first step in finding the area of a circle when given the diameter?

• Calculate the circumference

• Find the radius

• Multiply the diameter by pi

• Use the diameter directly in the formula