Finding the Fourth Proportional to 1,686.62, 2,327.02 and 978.32

Step by Step Solution

1. Step 1: Write the proportion equation
   1,686.62 : 2,327.02 = 978.32 : x
2. Step 2: Convert to fraction form
   1,686.62/2,327.02 = 978.32/x
3. Step 3: Cross multiply
   1,686.62x = 2,327.02 × 978.32
4. Step 4: Simplify right side
   1,686.62x = 2,276,565.31
5. Step 5: Solve for x
   x = 2,276,565.31/1,686.62
6. Step 6: Final answer
   x = 1,349.78