Exploring Area and Circumference of Circles

This video tutorial explains how to find the area and circumference of circles. It begins with a review of circle parts, including radius and diameter, and introduces formulas for calculating area and circumference. The tutorial provides examples of these calculations and applies them to real-world scenarios, such as determining the length of a gold rim for a lid and comparing circumferences of different circles. It concludes with a practical problem involving calculating the area of a donut to be frosted.

What is the formula to calculate the area of a circle?

• radius * radius / 2

• pi * diameter

• 2 * pi * radius

• pi * radius * radius

How do you find the circumference if you know the diameter?

• pi * radius

• pi * diameter

• radius / 2

• 2 * radius

How do you calculate the circumference of a circle using its radius?

• pi * diameter

• 2 * pi * radius

• pi * radius * radius

• 2 * radius

If a circle's diameter is 20 mm, what is its radius?

• 40 mm

• 10 mm

• 30 mm

• 20 mm

What is the area of a circle with a radius of 12 feet?

• 452.16 feet squared

• 144 feet squared

• 24 feet squared

• 36 feet squared

What is the circumference of a circle with a 12-foot radius?

• 24 feet

• 48 feet

• 36 feet

• 75.36 feet

If the diameter of a circle is 9 meters, what is its area in square meters?

• 63.6 meters squared

• 75.36 meters squared

• 56.52 meters squared

• 28.26 meters squared

How long will the gold rim need to be for a lid with a 7 cm radius?

• 28 cm

• 21 cm

• 14 cm

• 44 cm

What is the difference in circumference between Circle A (18 feet diameter) and Circle B (24 feet diameter)?

• 20.84 feet

• 18.84 feet

• 19.84 feet

• 17.84 feet

What is the area that Miguel will cover with frosting on the donut?

• 31.4 inches squared

• 28.26 inches squared

• 25.12 inches squared

• 3.14 inches squared