Calculating the Area of a Circle from the Radius

What does the area of a figure represent?

• The length of the figure

• The space a figure occupies on a surface

• The volume of the figure

• The perimeter of the figure

What is the formula for the area of a circle?

• Area = πd

• Area = r^2/π

• Area = πr^2

• Area = 2πr

What is the diameter of a circle?

• Twice the radius

• Half of the radius

• The line segment through the center connecting two points on the circle

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

What is the value of pi used in the video?

• 3.14

• 3.142

• 3.14159

• 22/7

Why do we use an approximate value for pi?

• Because pi is an exact number

• Because pi is a rational number

• Because pi is easier to calculate with an approximate value

• Because pi is an irrational number

How do you square a number?

• Multiply the number by 2

• Add the number to itself

• Divide the number by itself

• Multiply the number by itself

What is the area of a circle with a radius of 9 cm in terms of pi?

• 18π cm^2

• 9π cm^2

• 27π cm^2

• 81π cm^2

What does the squiggly equal sign represent?

• An exact value

• A rounded value

• An approximate value

• A mistaken value

What is the approximate area of a circle with a radius of 9 cm using 3.14 for pi?

• 254.34 cm^2

• 81 cm^2

• 28.26 cm^2

• 567.56 cm^2

How can the area of a circle be expressed?

• In square units only

• Using the diameter only

• Using the circumference

• In terms of pi or using an approximate value for pi