Finding the Fourth Proportional to 1,686.65, 2,327.57 and 978.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,686.65 : 2,327.57 = 978.62 : x
2. Step 2: Convert to fraction form
   1,686.65/2,327.57 = 978.62/x
3. Step 3: Cross multiply
   1,686.65x = 2,327.57 × 978.62
4. Step 4: Simplify right side
   1,686.65x = 2,277,814.82
5. Step 5: Solve for x
   x = 2,277,814.82/1,686.65
6. Step 6: Final answer
   x = 1,350.50