Finding the area of a circle

Module 10

Lesson 2

I CAN use the area formulas for a circle to find the area of a circle

Multiple Choice

Did you come into class on time, get out your materials, put your backpack away, and start following directions without wasting time?

• Yes, I did!

• No, I decided to take a nap instead.

• No, I was too busy talking to my friends.

• No, I don't really have any lame excuses either.

Multiple Select

Which equations will help me find the circumference of a circle?

C =

• πd

• 2πr

• 3dπ

• π day is March 14th

in² ; ft² ; cm² ; yd² : m²

Area: the amount of 2-dimensional space something takes up in square units

Let's try one!

A designer plans for a circular rug in a 9-foot by 9-foot square bedroom. What is the largest area of a rug that can fit in the bedroom?

Some text here about the topic of discussion

Multiple Choice

A designer plans for a circular rug in a 9-foot by 9-foot square bedroom. What is the largest area of a rug that can fit in the bedroom?

The question asks us to find the _____?

• area

• perimeter

• diameter

• radius

Multiple Choice

A designer plans for a circular rug in a 9-foot by 9-foot square bedroom. What is the largest area of a rug that can fit in the bedroom?

What is the formula for the Area of a circle?

• A = πd²

• A = πd

• A = πr²

• A = 2πr

Multiple Choice

If the diameter of the rug is 9 feet, and the Area formula is A = πr².

How do I get the radius from the diameter?

• Find the square root of the diameter.

  $$\sqrt[]{9}\ =\ 3$$

• Multiply the diameter by 2.

  9 × 2 = 18

• Divide the diameter by 2.

  9 ÷ 2 = 4.5

• Square the diameter.

  9² = 81