Finding the Fourth Proportional to 3,900.36, 5,385.78 and 2,784.72

Step by Step Solution

1. Step 1: Write the proportion equation
   3,900.36 : 5,385.78 = 2,784.72 : x
2. Step 2: Convert to fraction form
   3,900.36/5,385.78 = 2,784.72/x
3. Step 3: Cross multiply
   3,900.36x = 5,385.78 × 2,784.72
4. Step 4: Simplify right side
   3,900.36x = 14,997,889.28
5. Step 5: Solve for x
   x = 14,997,889.28/3,900.36
6. Step 6: Final answer
   x = 3,845.26