The area of a trapezoid = (a + b)/2 x h
Where a and b are the lengths of the parallel sides and h is the perpendicular distance between them.
When (a + b)/2 x 6 = 30
then (a + b)/2 = 5
a + b = 10
Possible values for (a,b) are (4,6) (3,7) (2,8) (1,9) assuming a < b but (7,3) is also valid.
Any positive real value is possible so (4.8, 5.2) and (0.3, 9.7) are valid
In general {a,b both real: 0
