Finding the Fourth Proportional to 13,680.79, 20,462.86 and 8,402.83

Step by Step Solution

1. Step 1: Write the proportion equation
   13,680.79 : 20,462.86 = 8,402.83 : x
2. Step 2: Convert to fraction form
   13,680.79/20,462.86 = 8,402.83/x
3. Step 3: Cross multiply
   13,680.79x = 20,462.86 × 8,402.83
4. Step 4: Simplify right side
   13,680.79x = 171,945,933.89
5. Step 5: Solve for x
   x = 171,945,933.89/13,680.79
6. Step 6: Final answer
   x = 12,568.42