Finding the Fourth Proportional to 1,677.28, 2,314.72 and 978.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,677.28 : 2,314.72 = 978.88 : x
2. Step 2: Convert to fraction form
   1,677.28/2,314.72 = 978.88/x
3. Step 3: Cross multiply
   1,677.28x = 2,314.72 × 978.88
4. Step 4: Simplify right side
   1,677.28x = 2,265,833.11
5. Step 5: Solve for x
   x = 2,265,833.11/1,677.28
6. Step 6: Final answer
   x = 1,350.90