A triangle has interior measures of 20° and 90°. What is the measure of the third angle?

Which expression is equivalent to (9x - 3 1/ + 1 3/8)

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

There are 8 movies that you would like to see currently showing in theatres. in how many different ways can you choose a movie to see this saturday and one to see this sunday?