Becky Afghani, LBUSD Math Curriculum Office, 2004 Area of a Parallelogram CA Standard (grade 5) Measurement and Geometry 1.1: Derive and use the formula for the area of a triangle and of a parallelogram by comparing it with the formula for the area of a rectangle (i.e., two of the same triangles make a parallelogram with twice the area; a parallelogram is compared with a rectangle of the same area by cutting and pasting a right triangle on the parallelogram).

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Remember: You know how to find the area of a rectangle. What is the formula? 8 units 4 units

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Today you’ll use what you know about rectangles to help you find the area of a parallelogram.

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Objective: Given three parallelograms, students will show they understand how to calculate the area of a parallelogram by using the formula to correctly find the area of all three parallelograms.

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Why am I learning this? /Carpenters and construction workers use area calculations. /In order to do well on standardized tests. /To pass the High School Exit Exam.

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD How is a parallelogram related to a rectangle? 8 units 4 units 8 units 4 units We’re going to cut a triangle off and slide it over:

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Has the area changed from the top figure to the bottom? 8 units 4 units 8 units 4 units What’s the area of the rectangle? 32 units 2 What’s the area of the parallelogram? 32 units 2 Explain to your partner. The area is the same, so...

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD How do you think you can find the area of any parallelogram? 8 units 4 units Area = 32 units 2

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD A = bh To find the area of a parallelogram, use the formula A = b x h The height The base Area of a Parallelogram Is x

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Use these three steps: 1. Write the Formula 2. Substitute the values for each variable 3. Simplify (Do the math!)

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Do this one with me: Count the length of the height. Count the length of the base.

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Is this right? The height is 4 units (straight up and down)… the answer is 7x4 = 28 units 2 4 units 5 units 7 units

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Is this right? This is a tricky one… The units should be units 2.

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Is this right? base height

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Find the area of each parallelogram.

Becky Afghani, LBUSD Math Curriculum Office, Clare Kay, Lindbergh and Becky Afghani, LBUSD Write in your notes... Formula Substitute Simplify