How many times is the sum of the interior angles of a convex dodecagon greater than the sum
How many times is the sum of the interior angles of a convex dodecagon greater than the sum of the interior angles of a convex hexagon?
Let us prove that the sum of the interior angles of a convex N-gon is 180 ° * (N – 2).
Choose any vertex of the N-gon and connect it by segments with all other vertices,
except for the neighboring ones. We obtain a partition of the N-gon into (N – 2) triangles, the sum of the angles of which coincides with the sum of the interior angles of the N-gon.
Therefore, the sum of the interior angles of a convex N-gon is 180 ° * (N – 2).
Then the sum of the interior angles of a convex dodecagon is
180 ° * (12 – 2) = 1800 °.
And the sum of the interior angles of a convex hexagon is 180 ° * (6 – 2) = 720 °.
Therefore, the sum of the interior angles of a convex dodecagon is greater than the sum of the interior angles of a convex hexagon
1800/720 = 2.5 times.