Finding the Fourth Proportional to 42,471.10, 63,690.45 and 12,879.10

Step by Step Solution

1. Step 1: Write the proportion equation
   42,471.10 : 63,690.45 = 12,879.10 : x
2. Step 2: Convert to fraction form
   42,471.10/63,690.45 = 12,879.10/x
3. Step 3: Cross multiply
   42,471.10x = 63,690.45 × 12,879.10
4. Step 4: Simplify right side
   42,471.10x = 820,275,674.60
5. Step 5: Solve for x
   x = 820,275,674.60/42,471.10
6. Step 6: Final answer
   x = 19,313.74