Exploring Area and Circumference of Circles

The video tutorial covers the basics of measuring circles, including understanding radius, diameter, and pi. It provides examples of calculating the circumference and area of circles, using both numerical values and expressions in terms of pi. The tutorial includes practical examples such as the circumference of Big Ben's clock face and the area watered by a sprinkler.

What is the radius of a circle if its diameter is 10 units?

• 5 units

• 20 units

• 2.5 units

• 10 units

What does the diameter of a circle represent?

• Half the circumference of the circle

• Twice the radius of the circle

• The distance from the center to any point on the circle

• The distance across the circle through its center

What is the value of Pi used in most circle calculations?

• 3.14

• 3.14159

• 22/7

• 3

If the diameter of a circle is 23 ft, what is its radius?

• 6.5 ft

• 23 ft

• 46 ft

• 11.5 ft

What formula is used to calculate the circumference of a circle?

• C = πd

• C = 2πr

• C = πr^2

• C = 2r

How many people with outstretched arms of 6 ft each would it take to encircle the base of the largest tree in Sequoia National Park?

• 12 people

• 6π people

• 18 people

• 36 people

If the circumference of a circle is calculated as 36π, what does this imply about the radius?

• The radius is 18 units

• The radius is 36 units

• The radius is 9 units

• The radius is 72 units

What is the area of a circle with a radius of 12 mm, written in terms of Pi?

• 144π mm^2

• 24π mm^2

• 72π mm^2

• 288π mm^2

What is the formula for calculating the area of a circle?

• A = r^2/π

• A = πd

• A = 2πr

• A = πr^2

If a rotating sprinkler waters a lawn in a circular area with a radius of 11 ft, what is the area watered?

• 379.94 ft^2

• 121π ft^2

• 22π ft^2

• 242 ft^2