Finding the Fourth Proportional to 1,431.72, 1,976.72 and 1,099.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,431.72 : 1,976.72 = 1,099.55 : x
2. Step 2: Convert to fraction form
   1,431.72/1,976.72 = 1,099.55/x
3. Step 3: Cross multiply
   1,431.72x = 1,976.72 × 1,099.55
4. Step 4: Simplify right side
   1,431.72x = 2,173,487.09
5. Step 5: Solve for x
   x = 2,173,487.09/1,431.72
6. Step 6: Final answer
   x = 1,518.10