Circles

Circles

By: Nadelyn Pichardo

What is Pi?

• A never-ending non-repeating irrational number (cannot be written as a fraction)

• A Greek symbol (π)

• Approximately 3.14

• Used when solving the area and circumference of circles

• Represents the ratio between circumferenc and diameter

Multiple Select

What is pi?

Check ALL applicable answers!

• a delicious dessert

• the ratio between circumference and diameter

• a Greek symbol

• exactly 3.14

• approximately 3.14

The Center

• The midpoint in the diameter

• The point that is equidistant (equally far) from all points in a circle

​The diameter is TWICE the radius

It goes from one side of the circle to the other

​The radius is HALF of the diameter!

Multiple Choice

Name the pictured part of the circle.

• Diameter

• Sector

• Radius

• Central Angle

• Arc

Multiple Choice

What is a straight line that goes through the center of a circle from side to the opposite side?

• Diameter

• Circumference

• Radius

• Center

Multiple Choice

Does this picture show the diameter or radius of a circle?

• Diameter

• Radius

Multiple Choice

A tire has a radius of 14 inches. What is its diameter?

• 14 inches

• 7 inches

• 28 inches

Fill in the Blanks

What is the length of the radius of the circle?

Multiple Choice

A pond has a diameter of 12 feet. What is its radius?

• 12 feet

• 6 feet

• 24 feet

Circumference

the distance around the outside of a circle (AKA perimeter)

Multiple Choice

The distance around a circle; is much like the perimeter of a rectangle.

• perimeter

• diameter

• circumference

• radius

Fill in the Blanks

The radius of the circle is 9 meters. What is the circle's circumference?

Fill in the Blanks

A cruise ship has a large, circular window with a diameter of 6 meters. What is the window's circumference?

(Round to the hundredths)

Area

• the measure inside the circle

• always in square units

Multiple Choice

What is the area of this circle?

• 28.26 cm²

• 28.26 cm

• 9.42 cm²

• 9.42 cm

Multiple Choice

What is the area of this circle?

• 28.26 in²

• 56.52 in²

• 254.34 in²

Multiple Choice

What is the area of this circle? Round to the nearest tenths place.

• 452.2 cm²

• 113.1 cm²

• 37.7 cm²