Finding the Fourth Proportional to 2,086.72, 3,131.15 and 917.54

Step by Step Solution

1. Step 1: Write the proportion equation
   2,086.72 : 3,131.15 = 917.54 : x
2. Step 2: Convert to fraction form
   2,086.72/3,131.15 = 917.54/x
3. Step 3: Cross multiply
   2,086.72x = 3,131.15 × 917.54
4. Step 4: Simplify right side
   2,086.72x = 2,872,952.60
5. Step 5: Solve for x
   x = 2,872,952.60/2,086.72
6. Step 6: Final answer
   x = 1,376.78