Finding the Fourth Proportional to 12,691.89, 19,016.17 and 8,987.96

Step by Step Solution

1. Step 1: Write the proportion equation
   12,691.89 : 19,016.17 = 8,987.96 : x
2. Step 2: Convert to fraction form
   12,691.89/19,016.17 = 8,987.96/x
3. Step 3: Cross multiply
   12,691.89x = 19,016.17 × 8,987.96
4. Step 4: Simplify right side
   12,691.89x = 170,916,600.38
5. Step 5: Solve for x
   x = 170,916,600.38/12,691.89
6. Step 6: Final answer
   x = 13,466.60