Finding the Fourth Proportional to 1,724.75, 2,380.10 and 978.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,724.75 : 2,380.10 = 978.77 : x
2. Step 2: Convert to fraction form
   1,724.75/2,380.10 = 978.77/x
3. Step 3: Cross multiply
   1,724.75x = 2,380.10 × 978.77
4. Step 4: Simplify right side
   1,724.75x = 2,329,565.58
5. Step 5: Solve for x
   x = 2,329,565.58/1,724.75
6. Step 6: Final answer
   x = 1,350.67