1. Geometry: Areas of Triangles
Chapter 9.1 C
Geometry: Areas of Triangles

2. Triangles are pretty much just parallelograms cut in HALF
What is a triangle?
Triangles are pretty much just parallelograms cut in HALF

3. Area of a triangle There are 2 formulas for triangles A = ½ b x h
BASE H E I G T
On some triangles the height IS part of the shape!!!
BASE

4. Just follow the formula and you’ll be fine!
ALWAYS write the formula, then plug in the numbers!
A = ½ b x h
A = ½ 4.2 x 7
A = ½ b x h
A = ½ 8 x 6
A = 14.7 in2
A = 24 in2
Area is always labeled in “square” measures

5. Working backwards A = ½ (b x h) 36 = ½ (12 x h) 72 = 12 x h 6 = h
A = 36 ft2 h
12 ft.
Since we know the AREA already, work the problem backwards to find the height!
A = ½ (b x h)
36 = ½ (12 x h)
36 x 2
72 = 12 x h
72 / 12
6 = h