Finding the Fourth Proportional to 1,388.12, 1,914.54 and 863.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.12 : 1,914.54 = 863.96 : x
2. Step 2: Convert to fraction form
   1,388.12/1,914.54 = 863.96/x
3. Step 3: Cross multiply
   1,388.12x = 1,914.54 × 863.96
4. Step 4: Simplify right side
   1,388.12x = 1,654,085.98
5. Step 5: Solve for x
   x = 1,654,085.98/1,388.12
6. Step 6: Final answer
   x = 1,191.60