Alexa is designing a paper airplane whose final shape, when viewed from the top or bottom, is a trapezoid. A sketch of her plane, viewed from the top, is shown on the left. A trapezoid has a base of 6 centimeters, a height of 3 centimeters, and a top side length of 2 centimeters. What are the dimensions of one of the identical triangular pieces of the plane? 2 cm base, 3 cm height 3 cm base, 3 cm height 3 cm base, 4 cm height 3 cm base, 6 cm height