Finding the Fourth Proportional to 13,680.86, 20,518.31 and 3,685.37

Step by Step Solution

1. Step 1: Write the proportion equation
   13,680.86 : 20,518.31 = 3,685.37 : x
2. Step 2: Convert to fraction form
   13,680.86/20,518.31 = 3,685.37/x
3. Step 3: Cross multiply
   13,680.86x = 20,518.31 × 3,685.37
4. Step 4: Simplify right side
   13,680.86x = 75,617,443.11
5. Step 5: Solve for x
   x = 75,617,443.11/13,680.86
6. Step 6: Final answer
   x = 5,527.25