Math formulas for problems found on the SAT and ACT. While the SAT lists many of the formulas at the beginning of each math test, the ACT does not. And, you will save time if you memorize these.
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| 19088196 | Quadratic Formula | -b±[√b²-4ac]/2a | |
| 19088197 | Slope | (y₂-y₁)/(x₂-x₁) | |
| 19088198 | Slope-Intercept | y=mx+b | |
| 19088199 | a³-b³ | (a-b)(a²+ab+b²) | |
| 19088200 | a³+b³ | (a+b)(a²-ab+b²) | |
| 19088201 | a²-b² | (a-b)(a+b) | |
| 19088202 | a²-2ab+b² | (a-b)² | |
| 19088203 | a²+2ab+b² | (a+b)² | |
| 19088204 | (a+b)(c+d) | ac+ad+bc+bd | |
| 19088205 | a(b+c) | ab+ac | |
| 19088206 | sine ratio | opposite ÷ hypotenuse | |
| 19088207 | cosine ratio | adjacent ÷ hypotenuse | |
| 19088208 | tangent ratio | opposite ÷ adjacent | |
| 19088451 | A function is ___________ a relation | always | |
| 19088452 | Direct Variation | y=kx | |
| 19088453 | Inverse Variation | y=k/x | |
| 19088454 | Slope intercept form | y=mx+b | |
| 19088455 | Point-Slope form | y-y₁=m(x-x₁) | |
| 19088456 | Standard form | Ax + By=C, where A, B, and C are not decimals or fractions, where A and B are not both zero, and where A is not a negative | |
| 19088457 | Undefined | When there is a vertical line that has different y points, but the same x point | |
| 19088458 | Zero | When there is a horizontal line that has different x points, but the same y point | |
| 19088459 | Dividing by a negative number in an inequality | You must flip the sign | |
| 19088460 | Graphing < or > on a coordinate plane | dotted line | |
| 19088461 | Graphing ≥ or ≤ on a coordinate plane | solid line | |
| 19088462 | Graphing ≥ or > on a coordinate plane | shade upwards or to the right | |
| 19088463 | Graphing ≤ or < on a coordinate plane | shade downwards or to the left | |
| 19088464 | Infinitely many solutions | when the system of equations have the same slope and y-intercept | |
| 19088465 | One solution | when the system of equations have different slopes | |
| 19088466 | No solution | when the system of equations have the same slope but different y-intercepts | |
| 19088467 | All direct variations are ____________________ | linear functions | |
| 19088468 | A linear function is a function that _____________ a line | graphs | |
| 19088469 | A parent function is the simplest ____________ of a function | equation | |
| 19088470 | Linear parent function | y=x or f(x)=x | |
| 19088471 | Elimination method | solving systems by adding or subtracting equations to eliminate a variable | |
| 19088472 | Solution of the system of linear equations | Any ordered pair in a system that makes all the equations true | |
| 19088473 | Graphing method | Graphing the system of equations and finding the point at which they intersect | |
| 19088474 | Substitution method | Replacing one variable with an equivalent expression containing the other variable | |
| 19088475 | Absolute value equation | A V-shaped graph that points upward of downward | |
| 19088476 | Translation | A shift of a graph horizontally, vertically, or both, which results in a graph of the same shape and size, but in a different position. | |
| 19088500 | Area of a circle | Πr² | |
| 19088501 | Area of a square | s², where s = length of a side | |
| 19088503 | Area of a triangle | ½(base x height) [or (base x height)÷2] | |
| 19088504 | Area of a trapezoid | ½(b₁ +b₂) x h [or (b₁ +b₂) x h÷2] | |
| 19088505 | Perimeter of a rectangle | 2Length + 2width [or (length + width) x 2] | |
| 19088506 | Perimeter of a square | 4s (where s = length of a side) | |
| 19088507 | Perimeter (circumference) of a circle | 2 pi r | |
| 19089060 | Area of rectangle, square, parallelogram | A=bh | |
| 19089064 | Circumference of a circle | ∏d OR 2∏r | |
| 19089065 | Area of a sector | x°/360 times (∏r²), where x is the degrees in the angle | |
| 19089412 | length of a sector | x°/360 times (2 pi r), where x is the degrees in the angle | |
| 19089465 | Circle | Is the set of points which are all the same distance (its radius) from a certian point( the center). | |
| 19089466 | Radius (Radii) | A segment connecting the center of a circle to any point on the circle | |
| 19089467 | Diameter | The distance across the circle through the center of the circle.The diameter is twice the radius. | |
| 19089468 | Chord | The distance from one point on the circle to another point on the circle. | |
| 19089469 | Sector | The part of a circle that looks like a piece of pie. A sector is bounded by 2 radii and an arc of the circle. | |
| 19089470 | Arc | Part of a circle connecting two points on the circle. | |
| 19089471 | Central Angle | An ange whose vertex is the center of the circle | |
| 19089472 | Circumference Formula | C =∏d | |
| 19089473 | Area of Circles | A=∏r2 |
