Finding the Fourth Proportional to 1,391.49, 2,088.66 and 1,086.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.49 : 2,088.66 = 1,086.72 : x
2. Step 2: Convert to fraction form
   1,391.49/2,088.66 = 1,086.72/x
3. Step 3: Cross multiply
   1,391.49x = 2,088.66 × 1,086.72
4. Step 4: Simplify right side
   1,391.49x = 2,269,788.60
5. Step 5: Solve for x
   x = 2,269,788.60/1,391.49
6. Step 6: Final answer
   x = 1,631.19