Finding the Fourth Proportional to 978.86, 1,350.59 and 553.49

Step by Step Solution

1. Step 1: Write the proportion equation
   978.86 : 1,350.59 = 553.49 : x
2. Step 2: Convert to fraction form
   978.86/1,350.59 = 553.49/x
3. Step 3: Cross multiply
   978.86x = 1,350.59 × 553.49
4. Step 4: Simplify right side
   978.86x = 747,540.51
5. Step 5: Solve for x
   x = 747,540.51/978.86
6. Step 6: Final answer
   x = 763.69