Finding the Fourth Proportional to 978.89, 1,350.89 and 536.78

Step by Step Solution

1. Step 1: Write the proportion equation
   978.89 : 1,350.89 = 536.78 : x
2. Step 2: Convert to fraction form
   978.89/1,350.89 = 536.78/x
3. Step 3: Cross multiply
   978.89x = 1,350.89 × 536.78
4. Step 4: Simplify right side
   978.89x = 725,135.45
5. Step 5: Solve for x
   x = 725,135.45/978.89
6. Step 6: Final answer
   x = 740.78