Finding the Fourth Proportional to 42,815.76, 64,233.10 and 12,828.78

Step by Step Solution

1. Step 1: Write the proportion equation
   42,815.76 : 64,233.10 = 12,828.78 : x
2. Step 2: Convert to fraction form
   42,815.76/64,233.10 = 12,828.78/x
3. Step 3: Cross multiply
   42,815.76x = 64,233.10 × 12,828.78
4. Step 4: Simplify right side
   42,815.76x = 824,032,324.65
5. Step 5: Solve for x
   x = 824,032,324.65/42,815.76
6. Step 6: Final answer
   x = 19,246.01