Finding the Fourth Proportional to 1,390.32, 2,080.88 and 868.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.32 : 2,080.88 = 868.54 : x
2. Step 2: Convert to fraction form
   1,390.32/2,080.88 = 868.54/x
3. Step 3: Cross multiply
   1,390.32x = 2,080.88 × 868.54
4. Step 4: Simplify right side
   1,390.32x = 1,807,327.52
5. Step 5: Solve for x
   x = 1,807,327.52/1,390.32
6. Step 6: Final answer
   x = 1,299.94