ACT MATH STUDY GUIDE

Degrees in triangle

180

Degrees in circle

360

Area of triangle

1/2x base x height

Area of circle

pi x radius to the second power

Circumference of circle

2 x pi x radius OR pi x diameter

Area of rectangle

Base x height

Area of parallelogram

Base x height

Area of square

side to the second power

Pythagorean Theorem

a to the second power plus b to the second equals c to the second power. (C=hypotenuse, only true for right triangles)

Slope-intercept form of a line:

y=mx + b

Point slope form of a line:

y - y1 = m (x - x1)

Slope formula [between 2 points (x1,y1) and x2, y2)]

y2 - y1/ x2-x1

Distance Formula [between 2 points (x1, y1) and (x2, y2)]

Square root (x2 - x1) to the second power + (y2 - y1) to the second power

Midpoint Formula [between 2 points (x1, y1) and (x2, y2)]

(x1 + x2/2, y1 + y2/2)

Equation of circle: Case 1: If center is (0,0):

x2 + y2 = r2

Equation of circle: Case 2: If center is (h,k):

(x-h)2 + (y-k)2 = r2

Logarithm Formula: log base x = y

b to the y power equals x

sin

opposite/hypotenuse

cos

adjacent/hypotenuse

tan

opposite/adjacent

Volume of a cylinder

pie x radius to the second power x height

Volume of box

V=length x width x height

Mean

Add all numbers, divide by number of numbers.

Median

The middle number from small to large, choose median.

FOIL

First, outside, inside, last (EX: (X-3)(X+2) = x2 + 2x -3x - 6)

Number of degrees in n-sided polygon

(n-2)(180)

Percent Formula

is/of = %/100