Find the value of QS

Mp model with mathematics explain how the number of text messages dario sent and the cost form an arithmetic sequence.then write an expression to find dario's text messaging bill if he sends n text messages over 250.

Find the measure of the interior angles of the following regular polygons: a triangle, a quadrilateral, a pentagon, an octagon, a decagon, a 30-gon, a 50-gon, and a 100-gon.

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much