Finding the Fourth Proportional to 1,223.10, 1,686.72 and 824.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.10 : 1,686.72 = 824.82 : x
2. Step 2: Convert to fraction form
   1,223.10/1,686.72 = 824.82/x
3. Step 3: Cross multiply
   1,223.10x = 1,686.72 × 824.82
4. Step 4: Simplify right side
   1,223.10x = 1,391,249.61
5. Step 5: Solve for x
   x = 1,391,249.61/1,223.10
6. Step 6: Final answer
   x = 1,137.48