Finding the Fourth Proportional to 1,123.71, 1,685.83 and 354.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.71 : 1,685.83 = 354.21 : x
2. Step 2: Convert to fraction form
   1,123.71/1,685.83 = 354.21/x
3. Step 3: Cross multiply
   1,123.71x = 1,685.83 × 354.21
4. Step 4: Simplify right side
   1,123.71x = 597,127.64
5. Step 5: Solve for x
   x = 597,127.64/1,123.71
6. Step 6: Final answer
   x = 531.39