AREA OF

TRIA

NGLES A

ND

TRAPE

ZOIDS

#3

4

You can divide any parallelogram into two congruent triangles. So the area of each triangle is half the area of the parallelogram.

FYI

VOCABULARY

Find the area of the triangle.

Example 1: Finding the Area of a Triangle

An altitude of a triangle is a perpendicular segment from one vertex to the line containing the opposite side. The length of the altitude is the height.

Reading Math

FYI

Example 2

Find the area of the triangle.

11 cm

4 cm

The diagram shows the floor plan for a triangulardining area. What is the area of the floor?

Example 3

6.2 m

34.8 m

The diagram shows the section of a forest being studied. What is the area of the section?

Example 4: Application

Example 5Mitch uses the piece of wood shown as part of a skateboard ramp. Its area is 0.8 m .

What is the height of the piece of wood?.

2 m

2

Example 6

Mitch wants his skateboard ramp to be at least 750 cm tall. Should he use this piece of wood to build the ramp? Explain.?.

VOCABULARY

Find the area of the trapezoid.

Example 7: Finding the Area of a Trapezoid

Example 8

Lisa wants to cut a hole in the shape of a trapezoid out of a piece of wood. The figure shows her plans, and each square of the grid represents 1 ft . What is the area of the remaining wood after she cuts out the hole?

2

Example 9

The figure shows a vegetable garden that is planted with squash and carrots. To the nearest percent, how much of the vegetable garden is for squash?