Finding the Fourth Proportional to 13,980.72, 20,978.22 and 7,739.55

Step by Step Solution

1. Step 1: Write the proportion equation
   13,980.72 : 20,978.22 = 7,739.55 : x
2. Step 2: Convert to fraction form
   13,980.72/20,978.22 = 7,739.55/x
3. Step 3: Cross multiply
   13,980.72x = 20,978.22 × 7,739.55
4. Step 4: Simplify right side
   13,980.72x = 162,361,982.60
5. Step 5: Solve for x
   x = 162,361,982.60/13,980.72
6. Step 6: Final answer
   x = 11,613.28