Finding the Fourth Proportional to 10,738.74, 15,987.78 and 10,686.78

Step by Step Solution

1. Step 1: Write the proportion equation
   10,738.74 : 15,987.78 = 10,686.78 : x
2. Step 2: Convert to fraction form
   10,738.74/15,987.78 = 10,686.78/x
3. Step 3: Cross multiply
   10,738.74x = 15,987.78 × 10,686.78
4. Step 4: Simplify right side
   10,738.74x = 170,857,887.55
5. Step 5: Solve for x
   x = 170,857,887.55/10,738.74
6. Step 6: Final answer
   x = 15,910.42