Finding the Fourth Proportional to 1,215.78, 1,822.59 and 556.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,215.78 : 1,822.59 = 556.98 : x
2. Step 2: Convert to fraction form
   1,215.78/1,822.59 = 556.98/x
3. Step 3: Cross multiply
   1,215.78x = 1,822.59 × 556.98
4. Step 4: Simplify right side
   1,215.78x = 1,015,146.18
5. Step 5: Solve for x
   x = 1,015,146.18/1,215.78
6. Step 6: Final answer
   x = 834.98