Answer:
The second base of the trapezoid b2 is 2.5 inches
Explanation:
Here, we want to calculate the second base of the trapezoid.
Mathematically, the area of a trapezoid can be given as;
A = 1/2(a + b) h
where a and b represents the parallel bases and h is the height of the trapezoid
so this, we have from the question
1/2(4.5 + b2) * 6 = 21
3(4.5 + b2) = 21
divide both sides by 3
4.5 + b2 = 7
b2 = 7-4.5
b2 = 2.5 inches