Finding the Fourth Proportional to 12,491.60, 17,239.56 and 7,187.60

Step by Step Solution

1. Step 1: Write the proportion equation
   12,491.60 : 17,239.56 = 7,187.60 : x
2. Step 2: Convert to fraction form
   12,491.60/17,239.56 = 7,187.60/x
3. Step 3: Cross multiply
   12,491.60x = 17,239.56 × 7,187.60
4. Step 4: Simplify right side
   12,491.60x = 123,911,061.46
5. Step 5: Solve for x
   x = 123,911,061.46/12,491.60
6. Step 6: Final answer
   x = 9,919.55