Finding the Fourth Proportional to 12,665.90, 17,478.18 and 7,631.75

Step by Step Solution

1. Step 1: Write the proportion equation
   12,665.90 : 17,478.18 = 7,631.75 : x
2. Step 2: Convert to fraction form
   12,665.90/17,478.18 = 7,631.75/x
3. Step 3: Cross multiply
   12,665.90x = 17,478.18 × 7,631.75
4. Step 4: Simplify right side
   12,665.90x = 133,389,143.91
5. Step 5: Solve for x
   x = 133,389,143.91/12,665.90
6. Step 6: Final answer
   x = 10,531.36