What is the sum of the interior angle measures of a 15-gon

Identify the converse of the following conditional: if a point is in the first quadrant, then its coordinates are positive. if the coordinates of a point are not positive, then the point is not in the first quadrant. if the coordinates of a point are positive, then the point is in the first quadrant. if a point is in the first quadrant, then its coordinates are positive. if a point is not in the first quadrant, then the coordinates of the point are not positive.

Need this asap if anyone can i would be very grateful. if you could show workings that would really

Ntriangle abc, m∠a = 35° and m∠b = 40°, and a=9. which equation should you solve to find b?