Circles Area and Circumference

Circles Area and Circumference

Please work on your warm ups

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​Kayne--Please pass out boards

​Savannah--Please pass out markers

​Jaden--Please pass out tissues

​Agenda

​1. Warm Ups

​2. Inequalities Rapid Board Problems

​3. Circles--Radius and Diameter Review

​4. Video and Notes on area and circumference

​5. Area and Circumference Quizizz Practice

​5.5 Vocab Review Together (if time permits)

​6. Area, Circumference, and Equations practice on delta math

Circle Circumference and Area

I can use the formulas for circumference and area of circles and semi-circles.

Radius and Diameter Relationship

RADIUS

a straight line from the center to the circumference of a circle or sphere.

Diameter

a straight line passing from side to side through the center of a body or figure, especially a circle or sphere.

Example 1

The Radius of this circle is 5 inches. What is the diameter?

Example 2

The DIameter of this circle is 22 centimeters. What is the radius?

Multiple Choice

What is the radius of this circle?

• 9 in

• 18 in

• 12 in

• 27 in

Find the Circumference

Circumference

• There are two fomulas for finding circumference

• C = πd

• C = 2πr

• Circumference is a little more than 3 times the diameter

Multiple Choice

What is the circumference?

• 48
• 96
• 24
• 18

Area

• the measure inside the circle

• always in square units

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• A = π r²

Find the Area of the Circle

Multiple Choice

Find the area of the circle

• 43.96
• 153.86
• 87.82
• 307.72

Multiple Choice

Find the area of the circle

• 56.52
• 254.34
• 1017.36
• 113.04

Multiple Choice

what is the area of a circle with the diameter of 10cm ?

• 66cm
• 78.5cm
• 66.5cm
• 10m

Multiple Choice

Marisa purchases a pot for her father's garden. The diameter of the bottom of the pot is 18 cm. What is the area of the pot's bottom? (Round to the nearest whole number.)

• 28 cm²
• 57 cm²
• 254 cm²
• 1017 cm²

Multiple Choice

a line that goes from one edge of the circle to another and crosses the center point

• center
• diameter
• dime eater
• radius

Multiple Choice

a line from the center point to the edge of the circle

• diameter
• radio
• radius
• pi

Multiple Choice

What is the area of a circle with a diameter of 10 cm ?

• 31.4 cm²
• 78.5 cm²
• 15.7 cm²
• 314 cm²