Finding the Fourth Proportional to 21,318.50, 31,978.05 and 17,365.20

Step by Step Solution

1. Step 1: Write the proportion equation
   21,318.50 : 31,978.05 = 17,365.20 : x
2. Step 2: Convert to fraction form
   21,318.50/31,978.05 = 17,365.20/x
3. Step 3: Cross multiply
   21,318.50x = 31,978.05 × 17,365.20
4. Step 4: Simplify right side
   21,318.50x = 555,305,233.86
5. Step 5: Solve for x
   x = 555,305,233.86/21,318.50
6. Step 6: Final answer
   x = 26,048.05