1. Geometry

3. Perimeter
The perimeter is the distance around a two-dimensional object.
The perimeter of a polygon can always be calculated by adding all the length of the sides together.

4. Perimeter Square = 4S
The perimeter of a square is the distance around the outside of the square. A square has four sides of equal length.
The formula for finding the perimeter of a square is:
4S (Length of a Side)

5. Perimeter Square Example:
Find the perimeter of a square with sides that measure 25 m.
Solution:
P = 4S
P = 4 (25m)
P = 100 m
So, the perimeter is 100 m.

6. Perimeter Rectangle
2L + 2W or
2 (L + W)
L = Length
W= Width

7. Perimeter Rectangle Example:
Find the perimeter of a rectangular field of length 45 m and width 35 m.
Solution:
P = 2 (L + W)
P = 2 ( )
P = 2 (80)
P = 160
So, the perimeter is 160 m.

8. Circumference Circle Circumference = 2π r Circumference = π d
P stands for the perimeter,
r stands for the radius
π is the mathematical constant pi (π = )
d stands for the circle's diameter (twice the radius of a circle)

9. Circumference Circle

10. Circumference Example:
The diameter of a circle is 3 centimeters. What is the circumference?
Circumference = π d
= 3.14 · (3 cm) 
= 9.42 cm

11. Area Area is a count of how many unit squares fit inside a figure.
The solution is labeled using square units.

12. Area of a Square
The area A of any square is equal to the square of the length s of a side. Formula: A = s2

13. Area of a Rectangle
The area A of any rectangle is equal to the product of the length l and the width w. Formula: A = lw or A = bh

14. Area of a Triangle
The area A of any triangle is equal to one-half the product of any base b and corresponding height h. Formula: A = 1/2bh

15. Area of a Trapezoid
The area A of any trapezoid is equal to one-half the product of the height h and the sum of the bases, b1 and b2. Formula: A = 1/2h(b1 + b2)

16. Area of a Circle
The area A of any circle is equal to the product of PI and the square of the radius r. Formula: A = (PI)r2