Finding the Fourth Proportional to 2,621.62, 3,932.84 and 978.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,621.62 : 3,932.84 = 978.40 : x
2. Step 2: Convert to fraction form
   2,621.62/3,932.84 = 978.40/x
3. Step 3: Cross multiply
   2,621.62x = 3,932.84 × 978.40
4. Step 4: Simplify right side
   2,621.62x = 3,847,890.66
5. Step 5: Solve for x
   x = 3,847,890.66/2,621.62
6. Step 6: Final answer
   x = 1,467.75