Estimating Math Cheat Sheat
Imperial Notation
' = feet
“ = inches
Fractional Notation for Lengths (example) 10’-11 ¼”
Common Decimal Conversions for the Imperial System
1″ = 0.083′
2″ = 0.167′
3″ = 0.250′
4″ = 0.333′
5″ = 0.417’
6″ = 0.500′
7″ = 0.583′
8″ = 0.667′
9″ = 0.750′
10″ = 0.833′
11″ = 0.917′
Order of Operations
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
Helpful Equations
2𝝅r = perimeter of a circle
2𝝅r (degree of angle ÷ 360) = length of an arc
a2 + b2 = c2 (pythagorean theorem)
a x b ÷ 2 = area of a right triangle
𝝅r2 = area of a circle
Area of Other Triangles
Create a line in the triangle from the angle opposite the longest side (hypotenuse) to the hypotenuse so that it forms two right triangles. Then use the equation to find the area of each right triangle and add them together.