Finding the Fourth Proportional to 1,225.86, 1,691.91 and 728.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,225.86 : 1,691.91 = 728.79 : x
2. Step 2: Convert to fraction form
   1,225.86/1,691.91 = 728.79/x
3. Step 3: Cross multiply
   1,225.86x = 1,691.91 × 728.79
4. Step 4: Simplify right side
   1,225.86x = 1,233,047.09
5. Step 5: Solve for x
   x = 1,233,047.09/1,225.86
6. Step 6: Final answer
   x = 1,005.86