Finding the Fourth Proportional to 1,258.80, 1,735.35 and 978.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,258.80 : 1,735.35 = 978.54 : x
2. Step 2: Convert to fraction form
   1,258.80/1,735.35 = 978.54/x
3. Step 3: Cross multiply
   1,258.80x = 1,735.35 × 978.54
4. Step 4: Simplify right side
   1,258.80x = 1,698,109.39
5. Step 5: Solve for x
   x = 1,698,109.39/1,258.80
6. Step 6: Final answer
   x = 1,348.99