Equations and Formulas
This is the equation of a line
y=mx+b
These lines have the same exact slopes
Parallel
These congruent angles are found between two parallel lines on opposite top and bottom sides of a transversal
alternate interior angles
How many sides does a decagon have
10
Instead of perimeter of a circle, we say this
This is the midpoint formula
y2-y1/x2-x1
Perpendicular line have these kinds of sloped
negative reciprocal
This angles add up to 180 degrees
supplementary
When a polygon is regular it means this
All sides have the same length and all angles have the same number of degrees
The difference between radius and diameter
The radius is half the diameter or the diameter is double the radius
This is the distance formula
Square root of (y2-y1)2 + (x2-x1)2
The line that has two endpoints on a circle and goes through its center
diameter
Congruent pairs of angles made by parallel lines and a transversal include vertical, alternate interior and exterior, and these
Corresponding angles
What is the formula for finding the area of a polygon
A = 1/2ap
When you know the central angle of a circle and the circumference you are able to find this
arc
How you find a polygon's central angle
Divide 360 by the number of sides of the polygon
This line goes through two parallel lines creating pairs of congruent angles
transversal
Right angles are formed by these lines
perpendicular
How do you find the area of a trapezoid
1/2(b1 + b2)h
The number of degrees in a semicircle
180
This is the point-slope formula
y-y1 =m(x-x1)
A centroid divides a median into two parts. The top accounts for this much of the lines length and the bottom for this much.
2/3 and 1/3
When a line extends outside of a triangle and it creates this angle, which is supplementary to its adjacent angle
exterior angle
You use this formula to find the number of degrees of an angle in a regular polygon
(n-2)180/n
The way you find the sector of a circle
x/360 *pi(r2)
central angle divided by 360 times the circle's area