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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 % = Tax Amt. 2. Total amt. = original price+tax amount |
tip | 1. Original price x tip % (as a decimal) = tip amt. 2. Total amt. = original price + tip amt. |
discount | 1. original price x discount % (as a decimal) = discount amt. 2. total amt. = original price discount amt. |
simple interest | Interest = principal x rate x time ( I = prt ) |
area of a rectangle | A = Base x Height or l x w |
area of a triangle | A = ( b x h ) /2 |
area of a trapezoid | A = [h(b1 + b2) /2 |
area of a circle | A = pi x r^2 |
circumference of a circle | C = 2 x pi x r |