Finding the Fourth Proportional to 1,686.41, 2,327.55 and 978.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,686.41 : 2,327.55 = 978.15 : x
2. Step 2: Convert to fraction form
   1,686.41/2,327.55 = 978.15/x
3. Step 3: Cross multiply
   1,686.41x = 2,327.55 × 978.15
4. Step 4: Simplify right side
   1,686.41x = 2,276,693.03
5. Step 5: Solve for x
   x = 2,276,693.03/1,686.41
6. Step 6: Final answer
   x = 1,350.03