Finding the Fourth Proportional to 978.72, 1,468.62 and 393.77

Step by Step Solution

1. Step 1: Write the proportion equation
   978.72 : 1,468.62 = 393.77 : x
2. Step 2: Convert to fraction form
   978.72/1,468.62 = 393.77/x
3. Step 3: Cross multiply
   978.72x = 1,468.62 × 393.77
4. Step 4: Simplify right side
   978.72x = 578,291.15
5. Step 5: Solve for x
   x = 578,291.15/978.72
6. Step 6: Final answer
   x = 590.86