Finding the Fourth Proportional to 11,687.31, 17,520.54 and 4,290.05

Step by Step Solution

1. Step 1: Write the proportion equation
   11,687.31 : 17,520.54 = 4,290.05 : x
2. Step 2: Convert to fraction form
   11,687.31/17,520.54 = 4,290.05/x
3. Step 3: Cross multiply
   11,687.31x = 17,520.54 × 4,290.05
4. Step 4: Simplify right side
   11,687.31x = 75,163,905.02
5. Step 5: Solve for x
   x = 75,163,905.02/11,687.31
6. Step 6: Final answer
   x = 6,431.24