derive = obtain or receive

This is a parallelogram. What happens if we cut out a side of the parallelogram and paste it on

the other side?What shape does it now form?

What can we derive from the area of a parallelogram and a rectangle?That’s right! They are the same!

The length time the height.

Let’s see what that looks like

12 inches

6 inches

=72in²6in x 12 in

Let’s see how that works. Remember that the area of a rectangle is length

times the width.

12 inches

6 inches

=72in²6in x 12 in

The length time the height.

Let’s see what that looks like again

3 cm

15 cm

=45cm²3cm x 15 in

Let’s see how that works. Remember that the area of a rectangle is length

times the width.

15 cm

3 cm

=45cm²15cm x 3cm

Why else is it important to use the distributive property in equations and expressions with

variables

It is important to derive and use the formula to figure out the area of a parallelogram because it will help you on your test. You can see examples of how it will look like on the CST’s below.

It will also prepare you for junior and high school.

We are going to use the formula for finding the area of parallelograms.

1. Look at the length of the parallelogram

2. Look at the height of the parallelogram

3. Remember the formula for finding the area of parallelogram L x W

4. Put in the numbers in the formula

5. 5 ft x 6 ft= 35 ft²

6 ft

5 ft

We are going to use the formula for finding the area of triangles.

1. Look at the length of the parallelogram

2. Look at the height of the parallelogram

3. Remember the formula for finding the area of parallelogram L x W

4. Put in the numbers in the formula8m x 20m= 160 m²

20 m

8 m

We are going to use the formula for finding the area of triangles.

1. Look at the length of the parallelogram

2. Look at the height of the parallelogram

3. Remember the formula for finding the area of parallelogram L x W

4. Put in the numbers in the formula3 cm x 6 cm= 18 cm²

6 cm

3 cm

We are going to use the formula for finding the area of triangles.

1. Look at the length of the parallelogram

2. Look at the height of the parallelogram

3. Remember the formula for finding the area of parallelogram L x W

4. Put in the numbers in the formula80 yds x 120 yds= 160 yds²

120 yds

80 yds

Let’s review what we learned:What is the formula for the area of a

rectangle?Why is the formula for the area of a triangle?What do you think is the most important

reason to know how use the formula for solving the area of a triangle?