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7th Math Formulas
2011-2012 7th Grade Math Formulas
| Question | Answer |
|---|---|
| Percent Proportion | is\of =%\100 |
| Percent of Change Proportion | change\original=%\100 |
| Sales Tax | 1. original price x tax %(as a decimal) = tax amount 2.total amount = original price + tax amount |
| Tip | 1.original price x tip %(as a decimal) = tip amount 2. total amount. = original price + tip amount |
| Discount | 1.original price x discount %(as a decimal) = discount amount 2. total amount =original price =discount amount |
| Simple Interest | Interest = principal x rate x time(i=prt) |
| Area of a Rectangle | Area = base x height or length x width |
| Area of a Triangle | Area = (base x height)\2 |
| Area of a Trapezoid | Area = (height x (base 1 + base 2))\2 |
| Area of a Circle | Area = pi x radius ^2 |
| Circumference of a circle | Circumference = 2 x pi x radius |