Finding the Fourth Proportional to 1,687.06, 2,328.16 and 978.93

Step by Step Solution

1. Step 1: Write the proportion equation
   1,687.06 : 2,328.16 = 978.93 : x
2. Step 2: Convert to fraction form
   1,687.06/2,328.16 = 978.93/x
3. Step 3: Cross multiply
   1,687.06x = 2,328.16 × 978.93
4. Step 4: Simplify right side
   1,687.06x = 2,279,105.67
5. Step 5: Solve for x
   x = 2,279,105.67/1,687.06
6. Step 6: Final answer
   x = 1,350.93