Finding the Area of a Circle: Key Concepts and Practice

This video tutorial covers essential circle vocabulary, including radius, diameter, and pi. It explains how to calculate the area of a circle using the formula A = πr², with step-by-step examples. The video also provides practice problems for viewers to solve, reinforcing the concepts of radius and diameter in the context of circle area calculations.

What is the definition of a radius in a circle?

• The total area inside the circle

• A segment outside the circle

• A line across the center of the circle

• A line from the center to the perimeter of the circle

How long is the diameter compared to the radius?

• Four times as long

• The same length

• Twice as long

• Half as long

What value is commonly used to approximate pi in calculations?

• 2.718

• 3.14

• 22/7

• 3.14159

What is the formula for the area of a circle?

• A = 2πr

• A = πr

• A = πr^2

• A = 2πr^2

If the radius of a circle is 5 cm, what is the area?

• 78.5 cm²

• 25 cm²

• 314 cm²

• 50 cm²

How do you find the radius if you are given the diameter?

• Multiply the diameter by 2

• Divide the diameter by 2

• Square root the diameter

• Square the diameter

What is the area of a circle if the diameter is 8 cm?

• 25.12 cm²

• 64 cm²

• 50.24 cm²

• 16 cm²

What should you check if the area calculation for a circle seems incorrect?

• If the formula was written correctly

• If the diameter was used instead of the radius

• All of the above

• If pi was used correctly

What is the area of circle number one from the practice problems?

• 314 mm squared

• 12.56 inches squared

• 78.5 cm squared

• 50.24 cm squared

What is the area of circle number two from the practice problems?

• 314 mm squared

• 12.56 inches squared

• 50.24 cm squared

• 78.5 cm squared