Finding the Fourth Proportional to 20,978.52, 28,935.62 and 13,806.15

Step by Step Solution

1. Step 1: Write the proportion equation
   20,978.52 : 28,935.62 = 13,806.15 : x
2. Step 2: Convert to fraction form
   20,978.52/28,935.62 = 13,806.15/x
3. Step 3: Cross multiply
   20,978.52x = 28,935.62 × 13,806.15
4. Step 4: Simplify right side
   20,978.52x = 399,489,441.03
5. Step 5: Solve for x
   x = 399,489,441.03/20,978.52
6. Step 6: Final answer
   x = 19,042.78