Each angle = 360/6 = 60

4x+15 = 60

x = 45/4 degrees

sum of 6-exterior angles = 360 degrees,

SO,

6 * (4x + 15) = 360,

4x + 15 = 360/6 = 60,

4x = 60 - 15 = 45,

Hence,

x = 45/4 = 11.25 degrees >========================< ANSWER

Well first I'm going to say that the answer to your other question about the triangle is 6 because the sum of the exterior angles is equal to 360 not 180, but I accidently deleted my answer so it won't let me repost. (the other answers say its 30 but thats wrong). As to this question, the sum of the exteriors is always 360 in any polygon, so (4x+15) times 6 (because there are six interior angles and an exterior for each interior) is equal to 360.

so 24x + 90 = 360 => 24x = 270 => 11.25

6(4x+15)=360°

4x+15=360°/6

4x+15=60°

4x=45°

x=45°/4

x=11.25°

Good luck !