Finding the Fourth Proportional to 20,155.05, 27,826.42 and 12,987.50

Step by Step Solution

1. Step 1: Write the proportion equation
   20,155.05 : 27,826.42 = 12,987.50 : x
2. Step 2: Convert to fraction form
   20,155.05/27,826.42 = 12,987.50/x
3. Step 3: Cross multiply
   20,155.05x = 27,826.42 × 12,987.50
4. Step 4: Simplify right side
   20,155.05x = 361,395,425.68
5. Step 5: Solve for x
   x = 361,395,425.68/20,155.05
6. Step 6: Final answer
   x = 17,930.76