Solve the right triangle. Round decimal answers to the nearest tenth

Ben is three times as old as samantha, who is two years older than half of michel's age. if michel is 12. how old is ben?

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.

Which number line correctly shows 0.8 + 0.3?