Finding the Fourth Proportional to 42,002.89, 63,012.84 and 12,420.07

Step by Step Solution

1. Step 1: Write the proportion equation
   42,002.89 : 63,012.84 = 12,420.07 : x
2. Step 2: Convert to fraction form
   42,002.89/63,012.84 = 12,420.07/x
3. Step 3: Cross multiply
   42,002.89x = 63,012.84 × 12,420.07
4. Step 4: Simplify right side
   42,002.89x = 782,623,883.70
5. Step 5: Solve for x
   x = 782,623,883.70/42,002.89
6. Step 6: Final answer
   x = 18,632.62