Finding the Fourth Proportional to 12,991.37, 17,916.31 and 8,513.49

Step by Step Solution

1. Step 1: Write the proportion equation
   12,991.37 : 17,916.31 = 8,513.49 : x
2. Step 2: Convert to fraction form
   12,991.37/17,916.31 = 8,513.49/x
3. Step 3: Cross multiply
   12,991.37x = 17,916.31 × 8,513.49
4. Step 4: Simplify right side
   12,991.37x = 152,530,326.02
5. Step 5: Solve for x
   x = 152,530,326.02/12,991.37
6. Step 6: Final answer
   x = 11,740.90