Finding the Fourth Proportional to 1,128.48, 1,691.91 and 478.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.48 : 1,691.91 = 478.86 : x
2. Step 2: Convert to fraction form
   1,128.48/1,691.91 = 478.86/x
3. Step 3: Cross multiply
   1,128.48x = 1,691.91 × 478.86
4. Step 4: Simplify right side
   1,128.48x = 810,188.02
5. Step 5: Solve for x
   x = 810,188.02/1,128.48
6. Step 6: Final answer
   x = 717.95