Day 7 Area and Surface

Day 7 Area and Surface

Math 6

Objective

Today I will describe the relationship between triangles and parallelograms so that I can show how any parallelogram can be decomposed into two identical triangles. I know I am successful when I complete Cool Down 7 to earn a 4.

Same Parallelograms, Different Bases

Here are two copies of a parallelogram. Each copy has one side labeled as the base b and a segment drawn for its corresponding height and labeled h. 

Open Ended

The base of the parallelogram on the left is 2.4 centimeters; its corresponding height is 1 centimeter. Find its area in square centimeters.

Open Ended

The height of the parallelogram on the right is 2 centimeters. How long is the base of that parallelogram? Explain your reasoning.

A Tale of Two Triangles

Two polygons are identical if they match up exactly when placed one on top of the other.

Multiple Select

Draw one line to decompose each of the following polygons into two identical triangles, if possible. Use a straightedge to draw your line. USE THE INTERACTIVE VERSION OR YOUR BOOK

• Book

• Online

Open Ended

Which quadrilaterals can be decomposed into two identical triangles?

Open Ended

Study the quadrilaterals that can, in fact, be decomposed into two identical triangles. What do you notice about them? Write a couple of observations about what these quadrilaterals have in common.

Let's Recap

Here are some important reminders about area

Multiple Choice

What does area mean?

• the distance around a shape
• half the distance around a shape
• the amount of space outside a shape
• the amount of space inside a shape

Multiple Choice

Base x Height is the formula to find the area of a

• triangle

• parallelogram

• classroom

• trapezoid

Multiple Choice

A parallelogram can be decomposed into two identical triangles.

• True

• False

Multiple Choice

The height of the triangle must be _________ to the base.

• parallel

• above

• perpendicular

• close

Multiple Choice

This quadrilateral can be decomposed into two identical triangles...

• True

• False

Poll

How I feel after this lesson

• 👎

• 👍