Geometric Formulas
Rectangle
Perimeter   \(P = 2l + 2w\)
Area   \(A = lw\)
Square
Perimeter   \(P = 4s\)
Area   \(A = s^2\)
Circle
Perimeter   \(P = 2\pi r\)
Area   \(A = \pi r^2\)
where \(\pi \approx 3.14\) or \(\dfrac{22}{7}\)
Triangle
Perimeter   \(P = a + b + c\)
Area   \(A = \tfrac{1}{2}bh\)
\(m\angle A + m\angle B + m\angle C = 180°\)
Right Triangle
Pythagorean theorem
\(a^2 + b^2 = c^2\)
Parallelogram
Area   \(A = bh\)
Trapezoid
Area   \(A = \tfrac{1}{2}h(B + b)\)
Cube
Surface area   \(S = 6s^2\)
Volume   \(V = s^3\)
Rectangular Solid
Surface area   \(S = 2wh + 2lh + 2lw\)
Volume   \(V = lwh\)
Sphere
Surface area   \(S = 4\pi r^2\)
Volume   \(V = \tfrac{4}{3}\pi r^3\)
Right Circular Cylinder
Surface area   \(S = 2\pi r^2 + 2\pi rh\)
Volume   \(V = \pi r^2 h\)
Right Circular Cone
Surface area   \(S = \pi rl + \pi r^2\)
Volume   \(V = \tfrac{1}{3}\pi r^2 h\)
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Metric System Units
Length
1 kilometer  (km) = 1000 meters
1 hectometer (hm) = 100 meters
1 dekameter  (dam) = 10 meters
1 meter       (m) = 1 meter
1 decimeter  (dm) = 0.1 meter
1 centimeter  (cm) = 0.01 meter
1 millimeter  (mm) = 0.001 meter
Weight (Mass)
1 metric ton (t) = 1,000,000 grams
1 kilogram  (kg) = 1000 grams
1 hectogram (hg) = 100 grams
1 dekagram  (dag) = 10 grams
1 gram      (g) = 1 gram
1 decigram  (dg) = 0.1 gram
1 centigram  (cg) = 0.01 gram
1 milligram  (mg) = 0.001 gram
Volume (Capacity)
1 kiloliter  (kL) = 1000 liters
1 hectoliter (hL) = 100 liters
1 dekaliter  (daL) = 10 liters
1 liter      (L) = 1 liter
1 deciliter  (dL) = 0.1 liter
1 centiliter  (cL) = 0.01 liter
1 milliliter  (mL) = 0.001 liter
Temperature: Celsius Scale
100°C = Boiling point of water
−273.15°C = Absolute zero: coldest possible temperature
0°C = Freezing point of water
37°C = Normal human body temperature

American System Units
Length
1 mile  (mi) = 1760 yards (yd)
1 mile  (mi) = 5280 feet (ft)
1 yard  (yd) = 3 feet (ft)
1 foot  (ft) = 12 inches (in.)
Weight (Mass)
1 ton   (T) = 2000 pounds (lb)
1 pound (lb) = 16 ounces (oz)
Volume (Capacity)
1 gallon (gal) = 4 quarts (qt)
1 quart  (qt) = 2 pints (pt)
1 pint   (pt) = 2 cups (c)
Temperature: Fahrenheit Scale
212° = Boiling point of water
−459.67° = Absolute zero
32° = Freezing point of water
98.6° = Normal human body temperature

Metric-American Conversion of Units
Conversions between American and Metric units for length, volume, weight, and temperature
Unit type American to Metric Metric to American
Units of Length 1 mile = 1.61 kilometers
1 yard = 0.914 meter
1 foot = 0.305 meter
1 inch = 2.54 centimeters
1 kilometer = 0.62 mile
1 meter = 3.28 feet
1 meter = 1.09 yards
1 centimeter = 0.394 inch
Units of Volume (Capacity) 1 gallon = 3.79 liters
1 quart = 0.946 liter
1 liter = 0.264 gallon
1 liter = 1.06 quarts
Units of Weight (Mass) 1 pound = 0.454 kilogram
1 ounce = 28.35 grams
1 kilogram = 2.2 pounds
1 gram = 0.0353 ounce
Units of Temperature \({}^{\circ}\text{F} = \tfrac{9}{5}C + 32\) \({}^{\circ}\text{C} = \tfrac{5}{9}({}^{\circ}\text{F} - 32)\)

Fraction, Decimal, and Percent Equivalents
Equivalent representations of common fractions as decimals and percentages
Notation \(\frac{1}{10}\) \(\frac{1}{8}\) \(\frac{1}{6}\) \(\frac{1}{5}\) \(\frac{1}{4}\) \(\frac{3}{10}\) \(\frac{1}{3}\) \(\frac{3}{8}\) \(\frac{2}{5}\) \(\frac{1}{2}\) \(\frac{3}{5}\) \(\frac{5}{8}\) \(\frac{2}{3}\) \(\frac{7}{10}\) \(\frac{3}{4}\) \(\frac{4}{5}\) \(\frac{5}{6}\) \(\frac{7}{8}\) \(\frac{9}{10}\) 1
Decimal 0.10.1250.160.20.25 0.30.30.3750.40.5 0.60.6250.60.70.75 0.80.830.8750.91
Percent 10% 12.5%
or 12½%
16.6%
or 16⅔%
20%25%30% 33.3%
or 33⅓%
37.5%
or 37½%
40%50%60% 62.5%
or 62½%
66.6%
or 66⅔%
70%75%80% 83.3%
or 83⅓%
87.5%
or 87½%
90%100%
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