probability of an event
when number of favorable outcomes is divided by number of possible outcomes
number of successes divided by the number of tries
I=Prt where the principal times rate (written as a decimal) times "time in years"
A = P(I +r)squared : where A is the balance, P is the principal, r is the annual interest rate (written as a decimal), and t is the time in years
Distance between two points in a coordinate plane is equal to the square root of the sum or the horizontal change squared and the vertical change squared.
Coordinates of the midpoint of a segment are the average of the endpoints x-coordinates and the average of the endpoints' y-coordinates.
difference of y-coordinates divided by difference of x-coordinates