Finding the Fourth Proportional to 10,185.50, 15,279.40 and 9,139.07

Step by Step Solution

1. Step 1: Write the proportion equation
   10,185.50 : 15,279.40 = 9,139.07 : x
2. Step 2: Convert to fraction form
   10,185.50/15,279.40 = 9,139.07/x
3. Step 3: Cross multiply
   10,185.50x = 15,279.40 × 9,139.07
4. Step 4: Simplify right side
   10,185.50x = 139,639,555.78
5. Step 5: Solve for x
   x = 139,639,555.78/10,185.50
6. Step 6: Final answer
   x = 13,709.64