Finding the Fourth Proportional to 1,215.96, 1,815.56 and 1,042.35

Step by Step Solution

1. Step 1: Write the proportion equation
   1,215.96 : 1,815.56 = 1,042.35 : x
2. Step 2: Convert to fraction form
   1,215.96/1,815.56 = 1,042.35/x
3. Step 3: Cross multiply
   1,215.96x = 1,815.56 × 1,042.35
4. Step 4: Simplify right side
   1,215.96x = 1,892,443.75
5. Step 5: Solve for x
   x = 1,892,443.75/1,215.96
6. Step 6: Final answer
   x = 1,556.34