1. 1-5 Geometric Formulas Polygons
The base and height of a triangle always make a right angle.

2. Examples Find area and perimeter. P = 6 + x + 4 + 5x P = 6x + 10
A = ½ bh
A = ½ (6)(x+4)
A = ½ (6x+24)
A = 3x + 12

3. Examples
Given a triangle with A=120 and h = 12, what is the length of the base?
The area of a square is 49 m2. What is the perimeter?
A = ½ bh
120 = ½ b(12)
240 = 12b
20 = b
A = w2
49 = w2
7 = w
P = 4w
P = 4(7) = 28

4. Example
What is the area and perimeter of the following figure? 4
P =
P = 30
A = 3(4) + 3(9)
A =
A = 39 3 3 3 2 3 3 9

5. Example
The length of a rectangle is 4 more than its width. If the perimeter of the rectangle is 44 inches, what is the area?
P = 4w + 8
44 = 4w + 8
36 = 4w
9 = w
l = 4 + w
l = 4 + 9
l = 13
A = lw
A = 13(9)
A = 117
L = 4 + w w w
L = 4 + w