Finding the Fourth Proportional to 39,115, 53,978.65 and 21,209.98

Step by Step Solution

1. Step 1: Write the proportion equation
   39,115 : 53,978.65 = 21,209.98 : x
2. Step 2: Convert to fraction form
   39,115/53,978.65 = 21,209.98/x
3. Step 3: Cross multiply
   39,115x = 53,978.65 × 21,209.98
4. Step 4: Simplify right side
   39,115x = 1,144,886,086.93
5. Step 5: Solve for x
   x = 1,144,886,086.93/39,115
6. Step 6: Final answer
   x = 29,269.75