Finding the Fourth Proportional to 28,390.91, 42,555.78 and 13,568.31

Step by Step Solution

1. Step 1: Write the proportion equation
   28,390.91 : 42,555.78 = 13,568.31 : x
2. Step 2: Convert to fraction form
   28,390.91/42,555.78 = 13,568.31/x
3. Step 3: Cross multiply
   28,390.91x = 42,555.78 × 13,568.31
4. Step 4: Simplify right side
   28,390.91x = 577,410,015.33
5. Step 5: Solve for x
   x = 577,410,015.33/28,390.91
6. Step 6: Final answer
   x = 20,337.85