Finding the Fourth Proportional to 2,621, 3,930.78 and 978.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,621 : 3,930.78 = 978.20 : x
2. Step 2: Convert to fraction form
   2,621/3,930.78 = 978.20/x
3. Step 3: Cross multiply
   2,621x = 3,930.78 × 978.20
4. Step 4: Simplify right side
   2,621x = 3,845,089.00
5. Step 5: Solve for x
   x = 3,845,089.00/2,621
6. Step 6: Final answer
   x = 1,467.03