Finding the Fourth Proportional to 3,991.28, 5,507.71 and 2,312.55

Step by Step Solution

1. Step 1: Write the proportion equation
   3,991.28 : 5,507.71 = 2,312.55 : x
2. Step 2: Convert to fraction form
   3,991.28/5,507.71 = 2,312.55/x
3. Step 3: Cross multiply
   3,991.28x = 5,507.71 × 2,312.55
4. Step 4: Simplify right side
   3,991.28x = 12,736,843.20
5. Step 5: Solve for x
   x = 12,736,843.20/3,991.28
6. Step 6: Final answer
   x = 3,191.17