+411 Two regular pentagons and a regular decagon, all with the same side length, can completely surround a point, as shown.
An equilateral triangle, a regular dodecagon, and a regular -gon, all with the same side length, also completely surround a point. Find n.
+34 We know that the interior angle measure of an equilateral triangle is 60 degrees, and the interior angle measure of a regular dodecagon is 150 degrees. Summing it up, we have 210 degrees. Because 360 degrees surround a point, the regular n-gon must have 150 as it's interior angle measure. A dodecagonn would work, so n = 12.
