What is the answer to 15 1/3

The construction of copying qpr is started below. the next step is to set the width of the compass to the length of ab. how does this step ensure that a new angle will be congruent to the original angle? by using compass take the measures of angle and draw the same arc according to it.

How many roots does the graphed polynomial function have? 1-02

What are the triple angle formulas? is it related to double angle identities?