Finding the Fourth Proportional to 2,621.48, 3,929.88 and 978.11

Step by Step Solution

1. Step 1: Write the proportion equation
   2,621.48 : 3,929.88 = 978.11 : x
2. Step 2: Convert to fraction form
   2,621.48/3,929.88 = 978.11/x
3. Step 3: Cross multiply
   2,621.48x = 3,929.88 × 978.11
4. Step 4: Simplify right side
   2,621.48x = 3,843,835.28
5. Step 5: Solve for x
   x = 3,843,835.28/2,621.48
6. Step 6: Final answer
   x = 1,466.28