Finding the Fourth Proportional to 13,680.72, 20,521.89 and 3,686.94

Step by Step Solution

1. Step 1: Write the proportion equation
   13,680.72 : 20,521.89 = 3,686.94 : x
2. Step 2: Convert to fraction form
   13,680.72/20,521.89 = 3,686.94/x
3. Step 3: Cross multiply
   13,680.72x = 20,521.89 × 3,686.94
4. Step 4: Simplify right side
   13,680.72x = 75,662,977.12
5. Step 5: Solve for x
   x = 75,662,977.12/13,680.72
6. Step 6: Final answer
   x = 5,530.63