Finding the Fourth Proportional to 28,142.98, 42,194.79 and 12,340.42

Step by Step Solution

1. Step 1: Write the proportion equation
   28,142.98 : 42,194.79 = 12,340.42 : x
2. Step 2: Convert to fraction form
   28,142.98/42,194.79 = 12,340.42/x
3. Step 3: Cross multiply
   28,142.98x = 42,194.79 × 12,340.42
4. Step 4: Simplify right side
   28,142.98x = 520,701,430.41
5. Step 5: Solve for x
   x = 520,701,430.41/28,142.98
6. Step 6: Final answer
   x = 18,502.00