Finding the Fourth Proportional to 1,109.27, 1,663.98 and 287.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,109.27 : 1,663.98 = 287.55 : x
2. Step 2: Convert to fraction form
   1,109.27/1,663.98 = 287.55/x
3. Step 3: Cross multiply
   1,109.27x = 1,663.98 × 287.55
4. Step 4: Simplify right side
   1,109.27x = 478,477.45
5. Step 5: Solve for x
   x = 478,477.45/1,109.27
6. Step 6: Final answer
   x = 431.34