Finding the Fourth Proportional to 39,978.72, 59,967.72 and 13,683.60

Step by Step Solution

1. Step 1: Write the proportion equation
   39,978.72 : 59,967.72 = 13,683.60 : x
2. Step 2: Convert to fraction form
   39,978.72/59,967.72 = 13,683.60/x
3. Step 3: Cross multiply
   39,978.72x = 59,967.72 × 13,683.60
4. Step 4: Simplify right side
   39,978.72x = 820,574,293.39
5. Step 5: Solve for x
   x = 820,574,293.39/39,978.72
6. Step 6: Final answer
   x = 20,525.28