Calculating Diameter and Circumference

Miss Toledo explains how to find the circumference of circles using the formula C = πd, where π is approximated as 3.14. She provides two examples: one to find the circumference given the radius, and another to find the diameter given the circumference. The first example involves calculating the circumference of a circle with a radius of 3.5 cm, while the second example involves finding the diameter of a circle with a circumference of 26.69 inches.

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

• Circumference = pi * diameter

• Circumference = 2 * pi * diameter

• Circumference = 2 * pi * radius

• Circumference = pi * radius^2

What value is used as an approximation for pi in this lesson?

• 3.14

• 3.1

• 3.14159

• 3.15

If a circle has a radius of 3.5 cm, what is its diameter?

• 10.5 cm

• 14 cm

• 7 cm

• 3.5 cm

How do you calculate the diameter from the radius?

• Diameter = radius - 2

• Diameter = radius / 2

• Diameter = radius * 2

• Diameter = radius + 2

What is the circumference of a circle with a diameter of 7 cm using pi as 3.14?

• 22 cm

• 20.98 cm

• 21.98 cm

• 21 cm

If the circumference of a circle is 26.69 inches, what is the formula to find the diameter?

• Diameter = Circumference + pi

• Diameter = Circumference - pi

• Diameter = Circumference / pi

• Diameter = Circumference * pi

What is the diameter of a circle with a circumference of 26.69 inches using pi as 3.14?

• 7.5 inches

• 8 inches

• 8.5 inches

• 9 inches

How do you reverse the multiplication of diameter by pi to find the diameter?

• Add pi to the circumference

• Subtract pi from the circumference

• Multiply the circumference by pi

• Divide the circumference by pi

What is the relationship between circumference and diameter in terms of pi?

• Circumference = pi / diameter

• Circumference = pi + diameter

• Circumference = pi - diameter

• Circumference = pi * diameter

What is the first step in finding the diameter if you know the circumference?

• Subtract pi from the circumference

• Add pi to the circumference

• Multiply the circumference by 2

• Divide the circumference by pi