Which of the following equations is the correct representation of the graph below?

Aright triangle includes one angle that measures 30º. what is the measure of the third angle? a. 30º b. 90º c. 60º d. 130º

Li buys supplies so he can make and sell key chains. he begins to make a profit only after he sells 4 key chains. what point on the graph makes the most sense in this situation?

Find the value of x. also give me an explanation so i can complete it to other questions as well, : )