Finding the Fourth Proportional to 1,123.02, 1,685.52 and 813.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.02 : 1,685.52 = 813.42 : x
2. Step 2: Convert to fraction form
   1,123.02/1,685.52 = 813.42/x
3. Step 3: Cross multiply
   1,123.02x = 1,685.52 × 813.42
4. Step 4: Simplify right side
   1,123.02x = 1,371,035.68
5. Step 5: Solve for x
   x = 1,371,035.68/1,123.02
6. Step 6: Final answer
   x = 1,220.85