Finding the Fourth Proportional to 711.18, 1,061.28 and 684.72

Step by Step Solution

1. Step 1: Write the proportion equation
   711.18 : 1,061.28 = 684.72 : x
2. Step 2: Convert to fraction form
   711.18/1,061.28 = 684.72/x
3. Step 3: Cross multiply
   711.18x = 1,061.28 × 684.72
4. Step 4: Simplify right side
   711.18x = 726,679.64
5. Step 5: Solve for x
   x = 726,679.64/711.18
6. Step 6: Final answer
   x = 1,021.79