Master Finding the area and circumference of a circle and shaded regions

The video tutorial explains how to calculate the area and circumference of circles and related figures. It covers the use of radius and diameter in these calculations, including examples with whole circles, shaded regions, and semi-circles. The instructor emphasizes leaving π in the answer for precision and demonstrates step-by-step calculations for each scenario.

What is the formula for the area of a circle?

• 2πR

• R²/π

• πR

• πR²

If a circle has a radius of 3 inches, what is its circumference?

• 12π inches

• 9π inches

• 6π inches

• 3π inches

How is the diameter of a circle related to its radius?

• Diameter is the square of the radius

• Diameter is double the radius

• Diameter is equal to the radius

• Diameter is half the radius

What is the area of a circle with a diameter of 5 inches?

• 25π inches squared

• 5π inches squared

• 25/4π inches squared

• 10π inches squared

How do you find the area of a ring-shaped figure?

• Subtract the area of the smaller circle from the larger circle

• Multiply the areas of the two circles

• Divide the area of the larger circle by the smaller circle

• Add the areas of the two circles

What is the circumference of a ring-shaped figure with radii of 2 feet and 1 foot?

• 4π feet

• 2π feet

• 6π feet

• 8π feet

How do you calculate the area of a semicircle?

• πR²

• 1/2πR²

• R²/2π

• 2πR