Finding the Fourth Proportional to 42,470.42, 63,705.78 and 12,888.50

Step by Step Solution

1. Step 1: Write the proportion equation
   42,470.42 : 63,705.78 = 12,888.50 : x
2. Step 2: Convert to fraction form
   42,470.42/63,705.78 = 12,888.50/x
3. Step 3: Cross multiply
   42,470.42x = 63,705.78 × 12,888.50
4. Step 4: Simplify right side
   42,470.42x = 821,071,945.53
5. Step 5: Solve for x
   x = 821,071,945.53/42,470.42
6. Step 6: Final answer
   x = 19,332.80