GRE MATH FORMULAS
Terms
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- a2-b2
- (a-b)(a+b)
- a2+2ab+b2
-
(a+b)2
a2-2ab+b2 = (a-b)2 - ax2+bx+c
- = 0
-
Finding the distance b/n two points
D = - square (x1-x2)2 + (y1-y2)2
-
Using two point to find the slope:
Slope = -
Change in y
--------- = Rise/Run
Change in x -
Finding the Midpoint
if the endpoints are
(x1, y1) and (x2, y2), the midpoint is -
(x1+x2) (y1+y2)
------ -------
2 2 -
-n
X = -
1
---
n
X -
Using an Equation to Find the Slop (slope intercept)
Y = - Mx+b
-
Length of an Arc
if n is the degree measure of the arc's central angle then
Length of Arc = - (n/360)(2PIr)
- Area of Circle =
- PIR2
-
if n is the degree measure of the sector's central agnle, then the
Area of a Sector - (n/360)(PIr2)
- In a 45-45-90 right triangle the sides =
- x, x and x square 2
- In a 30-60-90 righttriangle, the sides =
-
x, x sq 3, 2x
square 3 - Area of an Equilateral triangle with side s, A =
-
S2 sq 3
------
4
S square * square of 3 divided by 4 - Acute angel
- X<90 degrees