probability of an event
when number of favorable outcomes is divided by number of possible outcomes

Experimental probability
number of successes divided by the number of tries

Simple interest
I=Prt where the principal times rate (written as a decimal) times "time in years"

Compound interest
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 formula
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.

Midpoint formula
Coordinates of the midpoint of a segment are the average of the endpoints x-coordinates and the average of the endpoints' y-coordinates.

Slope formula
difference of y-coordinates divided by difference of x-coordinates

Please allow access to your computer’s microphone to use Voice Recording.

We can’t access your microphone!
Click the icon above to update your browser permissions above and try again
Example:

Reload the page to try again!
Reload

Press Cmd-0 to reset your zoom
Press Ctrl-0 to reset your zoom
It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.
Your microphone is muted
For help fixing this issue, see this FAQ .