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Area of Triangles
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Area of a Triangle
Let's use the same process as2 we did for the rectangle &
parallelogram. How many 1 ft tiles fit across the bottom
of the triangle?
Area of a Triangle
2
If we continue to build the triangle with rows of 10 ft ,
what happens?
10 ft
How tall is the triangle? How can you tell?
How does this help us find the area of the triangle?
4 ft
10 ft
See that the rectangle we built is twice as large as the
triangle. How do you find the area of a triangle?
Find the area of the rectangle, then divide by 2
2
20 ft
Is this true for all triangles?
Let's see!
Calculating base(height) results in 2 triangles!
The Area (A) of a triangle is found by using the formula:
Note: The base & height always form a right angle!
Example.
Find the area of the figure.
4 cm
10 cm
10 cm
click to reveal
6 cm
Try These.
Find the area of the figures.
20
13 ft
9 ft
12 ft
11 ft
14
16
15
click to reveal
click to reveal
73 Find the area.
11 in
5 in
8 in
10 in
74 Find the area
9m
8m
15 m
12 m