What is the sum, in inches, of diameters H and M?

• A. 5 in.
• B. 4 in.
• C. 7 in.
• D. 6 in.

Answer: (A)

When you’re dealing with two diameters, the total length you’re looking for is simply the sum of those two diameters. If the data you have are radii, convert them to diameters by doubling each radius, then add: D_H = 2r_H and D_M = 2r_M, so the total is D_H + D_M = 2(r_H + r_M).

In this problem, the measurements given for diameters H and M add up to 5 inches, so the sum is 5 inches. If you tried to get a different total, you’d be contradicting the measurements shown for the two diameters.