Finding the Fourth Proportional to 1,676.70, 2,314.71 and 978.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,676.70 : 2,314.71 = 978.78 : x
2. Step 2: Convert to fraction form
   1,676.70/2,314.71 = 978.78/x
3. Step 3: Cross multiply
   1,676.70x = 2,314.71 × 978.78
4. Step 4: Simplify right side
   1,676.70x = 2,265,591.85
5. Step 5: Solve for x
   x = 2,265,591.85/1,676.70
6. Step 6: Final answer
   x = 1,351.22