How to find the standard deviations

You give a $4 tip for a meal that cost $22. approximately what percent of the bill was your tip?

Angle xyz is formed by segments xy and yz on the coordinate grid below: a coordinate plane is shown. angle xyz has endpoints at 3 comma negative 1 and 6 negative 2 and 3 comma negative 3 and measures 36.87 degrees. angle xyz is rotated 270 degrees counterclockwise about the origin to form angle x′y′z′. which statement shows the measure of angle x′y′z′?

If the simple annual interest rate on a loan is 6, what is the interest rate in percentage per month?