Finding the Fourth Proportional to 10,105.79, 15,138.18 and 5,105.07

Step by Step Solution

1. Step 1: Write the proportion equation
   10,105.79 : 15,138.18 = 5,105.07 : x
2. Step 2: Convert to fraction form
   10,105.79/15,138.18 = 5,105.07/x
3. Step 3: Cross multiply
   10,105.79x = 15,138.18 × 5,105.07
4. Step 4: Simplify right side
   10,105.79x = 77,281,468.57
5. Step 5: Solve for x
   x = 77,281,468.57/10,105.79
6. Step 6: Final answer
   x = 7,647.25