Doctors have two ways of calculating maximum heart rates.

C. π(2ft)²(10ft) + 1/3π(2ft)²(13ft-10ft)

Step-by-step explanation:

Given:

diameter = 4ft

length of the cylindrical part = 10ft

entire length of the silo = 13ft

Find the volume of the silo = volume of cylinder and volume of the cone

Formulas:

Volume of cylinder: πr²h

Volume of come: 1/3πr²h

2ft= radius

height =10

volume π×2²×10

radius 2ft

height 13-10=3ft

Volume= 1/3×π×2²×3 cube feet

Therefore the third answer is correct: C. π(2ft)²(10ft) + 1/3π(2ft)²(13ft-10ft)