Finding the Fourth Proportional to 1,511.72, 2,086.12 and 839.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,511.72 : 2,086.12 = 839.55 : x
2. Step 2: Convert to fraction form
   1,511.72/2,086.12 = 839.55/x
3. Step 3: Cross multiply
   1,511.72x = 2,086.12 × 839.55
4. Step 4: Simplify right side
   1,511.72x = 1,751,410.92
5. Step 5: Solve for x
   x = 1,751,410.92/1,511.72
6. Step 6: Final answer
   x = 1,158.55