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10.07 Area of rectangles

Lesson

Are you ready?

Can you find area using a grid?

Find the area of the shape by counting the number of grid squares it covers.

Each grid square represents $1$1 square unit.

 

Learn

This video shows how we can use the dimensions of a rectangle to divide it into unit squares. Using this method, we can find the area by counting the unit squares.

Apply

question 1

What is the area of the rectangle?

  1. $\editable{}$ unit squares

 

Learn

The area of a rectangle can be found using the formula:

$\text{Area}=\text{Length}\times\text{Width}$Area=Length×Width

This video shows us how we can find the area of a rectangle by multiplying its length and width together.

Apply

question 2

Find the area of the rectangle shown.

width = $3$3 cm
length = $9$9 cm  
  1. $\text{Area }$Area $=$= $\text{length }\times\text{width }$length ×width cm2  
    $\text{Area }$Area $=$= $\editable{}\times\editable{}$× cm2 (Fill in the values for the length and width.)
    $\text{Area }$Area $=$= $\editable{}$ cm2 (Complete the multiplication to find the area.)

 

What about squares?

A square is a special kind of rectangle, so we can use the same method to work out the area. Instead of having a different number for our length and width, each side has the same length. Markers are often used, rather than write the length on every side, as this picture shows.

Remember!

When we calculate area, the unit of measurement is squared. If we have sides measured in centimeters (cm), for example, the area will be cm2

Outcomes

3.MD.C.7

Relate area to the operations of multiplication and addition.

3.MD.C.7a

A. Find the area of a rectangle with whole-number side lengths by tiling it, and show that the area is the same as would be found by multiplying the side lengths.

3.MD.C.7b

A. Find the area of a rectangle with whole-number side lengths by tiling it, and show that the area is the same as would be found by multiplying the side lengths.

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