Finding the Fourth Proportional to 978.95, 1,350.83 and 780.29

Step by Step Solution

1. Step 1: Write the proportion equation
   978.95 : 1,350.83 = 780.29 : x
2. Step 2: Convert to fraction form
   978.95/1,350.83 = 780.29/x
3. Step 3: Cross multiply
   978.95x = 1,350.83 × 780.29
4. Step 4: Simplify right side
   978.95x = 1,054,039.40
5. Step 5: Solve for x
   x = 1,054,039.40/978.95
6. Step 6: Final answer
   x = 1,076.70