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

Fill in the Blanks

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 diameter of the largest circular area rug that will fit in the room?

Type only the number.

ft

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

Fill in the Blanks

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?

A = π4.5²

Round answer to the nearest tenth (1 decimal place)