We can divide the trapezoid into a triangle and a rectangle:
Find the area of each figure, and then add them:
Area of a triangle = 1/2 x base x height
A1 = 1/2 x 2 x 3 = 3 in2
Area of a rectangle: base x height
A2 = 5 x 3 = 15 in2
Total area = A1 + A2 = 3 + 15 = 18 in2