A trapezoid can have 4 angles which are not equal to one another.
Trapezoids do not need to have any angles that are equal to one another. The formula $4481_w81_h39.png$ is for area of a trapezoid. Trapezoids can have right angles but do not have to have a 90 degree angle. This answer is correct because it is possible for a trapezoid to have 4 different angles.
B At least two angles in a trapezoid must equal each other.
C The perimeter of a trapezoid is equal to (a + b)*h
D A trapezoid will always have a right angle.