Answer:
Trapezoid:

Rhombus:

Triangle:

N-gon:

Explanation:
In the trapezoid, h is the height and b is the base.
In the rhombus, d is the diagonal.
In the triangle, b is the base and h the height.
In the n-gon, n is the sides of the n-gon, a is the apothem, s is the side, and p is the perimeter.