Finding the Fourth Proportional to 42,809.88, 64,203.78 and 12,818.20

Step by Step Solution

1. Step 1: Write the proportion equation
   42,809.88 : 64,203.78 = 12,818.20 : x
2. Step 2: Convert to fraction form
   42,809.88/64,203.78 = 12,818.20/x
3. Step 3: Cross multiply
   42,809.88x = 64,203.78 × 12,818.20
4. Step 4: Simplify right side
   42,809.88x = 822,976,892.80
5. Step 5: Solve for x
   x = 822,976,892.80/42,809.88
6. Step 6: Final answer
   x = 19,223.99