Topics
10. Area and Perimeter
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United States of AmericaAZ
3rd Grade

10.09 Other problems with area

Lesson
Practice
Lesson

Are you ready?

Can you find the area of a rectangle by using the length and width? 

We are going to find the area of a rectangle by first identifying the length and the width.

  1. Find the length and width of the rectangle.

    length = $\editable{}$ units
    width = $\editable{}$ units  

  2. Find the area of the rectangle by completing this table.

    $\text{Area }$Area $=$= $\text{length }\times\text{width }$length ×width units2
    $\text{Area }$Area $=$= $\editable{}\times\editable{}$× units2 (Fill in the values for the length and width.)
    $\text{Area }$Area $=$= $\editable{}$ units2 (Complete the multiplication to find the area.)

Learn

By breaking a shape into smaller rectangles, we can work out the area of those rectangles first. We can then add those two values together, to work out the total area of our shape.

Apply

The total area of this shape is $75$75 cm2.

If the area of rectangle $A$A is $27$27 cm2, what is the area of rectangle $B$B?

        $A$A        
               
                 
        $B$B        
                 

 

Remember!

Make sure to add all the smaller shapes together to get the total area of the shape. 

Outcomes

3.MD.C.7

Relate area to the operations of multiplication and addition.

3.MD.C.7d

D. Understand that rectilinear figures can be decomposed into non-overlapping rectangles and that the sum of the areas of these rectangles is identical to the area of the original rectilinear figure. Apply this technique to solve problems in real-world contexts.

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