Find the measure of the angle indicated

Explanation:

The arc measures shown are 138 and 58. Subtract the arc measures and divide by 2 to get the answer

(138-58)/2 = 80/2 = 40 degrees

The general formula is

(A - B)/2

where A and B are the arc measures. The value of A is always the larger arc measure. This formula works for two secant lines as this diagram shows, and it also works for a secant line and tangent line, and lastly it works if both lines were tangent.

answer: i think it is (1,-2)