Finding the Fourth Proportional to 42,818.92, 64,234.54 and 13,239.06

Step by Step Solution

1. Step 1: Write the proportion equation
   42,818.92 : 64,234.54 = 13,239.06 : x
2. Step 2: Convert to fraction form
   42,818.92/64,234.54 = 13,239.06/x
3. Step 3: Cross multiply
   42,818.92x = 64,234.54 × 13,239.06
4. Step 4: Simplify right side
   42,818.92x = 850,404,929.13
5. Step 5: Solve for x
   x = 850,404,929.13/42,818.92
6. Step 6: Final answer
   x = 19,860.49