Finding the Fourth Proportional to 1,089.72, 1,637.88 and 726.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,089.72 : 1,637.88 = 726.72 : x
2. Step 2: Convert to fraction form
   1,089.72/1,637.88 = 726.72/x
3. Step 3: Cross multiply
   1,089.72x = 1,637.88 × 726.72
4. Step 4: Simplify right side
   1,089.72x = 1,190,280.15
5. Step 5: Solve for x
   x = 1,190,280.15/1,089.72
6. Step 6: Final answer
   x = 1,092.28