Circle Area and Properties

This video tutorial explains how to find the area of a circle using the formula A = πr². It covers the difference between approximate and exact area calculations, using both numerical values and the π symbol. The tutorial also demonstrates how to calculate the area of shaded regions within a circle and how to determine the area covered by a sprinkler. Key concepts include understanding the formula, applying it to different scenarios, and rounding results appropriately.

What does the 'A' stand for in the formula A = πr²?

• Area

• Angle

• Altitude

• Arc

If the diameter of a circle is 20 cm, what is the radius?

• 20 cm

• 5 cm

• 10 cm

• 15 cm

What is the approximate area of a circle with a radius of 10 cm using π ≈ 3.14?

• 100 cm²

• 31.4 cm²

• 3140 cm²

• 314 cm²

When rounding to the nearest hundredth, what is 18.0864 rounded to?

• 18.08

• 18.00

• 18.09

• 18.10

What is the area of a semicircle with a diameter of 6 meters?

• 56.52 m²

• 14.13 m²

• 28.26 m²

• 7.07 m²

How do you find the area of a shaded region in a circle?

• Find the area of the whole circle and subtract the unshaded area

• Find the area of the whole circle and divide by the number of sections

• Find the area of the whole circle and multiply by the shaded fraction

• Find the area of the whole circle and add the shaded area

If a circle is divided into 5 equal sections and 3 are shaded, what fraction of the circle is shaded?

• 4/5

• 3/5

• 2/5

• 1/5

What is the area of a circle with a radius of 5 cm using π ≈ 3.14?

• 50 cm²

• 78.5 cm²

• 15.7 cm²

• 31.4 cm²

If a circle has an area of 78.5 cm² and is divided into 4 equal parts, what is the area of one part?

• 50 cm²

• 19.625 cm²

• 31.4 cm²

• 15.7 cm²

A sprinkler covers a circular area with a radius of 8 feet. What is the area covered by the sprinkler?

• 100.48 ft²

• 400.92 ft²

• 50.24 ft²

• 200.96 ft²