6 . C
Mark up the figure. The angles of the rectangle are right angles. To figure out the interior
angles of the pentagon, use the formula for the degree measure of each interior angle of a
regular polygon of n sides:
Label all the angles you can:
The angles marked a° are equal and together with 108° add up to 180°:
So the right triangle in the upper left looks like this:
The leg on top (opposite the 54° angle) is half of BC, or The hypotenuse of this right
triangle is one side of the pentagon whose perimeter you are looking for, so call the
hypotenuse x:
