Finding the Fourth Proportional to 20,878.50, 28,812.42 and 12,495

Step by Step Solution

1. Step 1: Write the proportion equation
   20,878.50 : 28,812.42 = 12,495 : x
2. Step 2: Convert to fraction form
   20,878.50/28,812.42 = 12,495/x
3. Step 3: Cross multiply
   20,878.50x = 28,812.42 × 12,495
4. Step 4: Simplify right side
   20,878.50x = 360,011,187.90
5. Step 5: Solve for x
   x = 360,011,187.90/20,878.50
6. Step 6: Final answer
   x = 17,243.15