Finding the Fourth Proportional to 12,615.30, 17,400.78 and 7,891.38

Step by Step Solution

1. Step 1: Write the proportion equation
   12,615.30 : 17,400.78 = 7,891.38 : x
2. Step 2: Convert to fraction form
   12,615.30/17,400.78 = 7,891.38/x
3. Step 3: Cross multiply
   12,615.30x = 17,400.78 × 7,891.38
4. Step 4: Simplify right side
   12,615.30x = 137,316,167.28
5. Step 5: Solve for x
   x = 137,316,167.28/12,615.30
6. Step 6: Final answer
   x = 10,884.89