If the length of the shorter base of a trapezoid is 5 cm, and the length of the longer base is 15 cm, what is the average length of the bases?
Correct: C
To find the average length of the bases of the trapezoid, we need to add the lengths of the two bases and then divide by 2. The formula for average is (sum of values)/number of values. Here, the sum of the lengths of the bases is 5 cm + 15 cm = 20 cm, and there are 2 bases. So, the average length is 20 cm / 2 = 10 cm.