Finding the Fourth Proportional to 1,123.61, 1,684.33 and 711.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.61 : 1,684.33 = 711.72 : x
2. Step 2: Convert to fraction form
   1,123.61/1,684.33 = 711.72/x
3. Step 3: Cross multiply
   1,123.61x = 1,684.33 × 711.72
4. Step 4: Simplify right side
   1,123.61x = 1,198,769.57
5. Step 5: Solve for x
   x = 1,198,769.57/1,123.61
6. Step 6: Final answer
   x = 1,066.90