Finding the Fourth Proportional to 2,147.90, 3,221.82 and 978.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,147.90 : 3,221.82 = 978.30 : x
2. Step 2: Convert to fraction form
   2,147.90/3,221.82 = 978.30/x
3. Step 3: Cross multiply
   2,147.90x = 3,221.82 × 978.30
4. Step 4: Simplify right side
   2,147.90x = 3,151,906.51
5. Step 5: Solve for x
   x = 3,151,906.51/2,147.90
6. Step 6: Final answer
   x = 1,467.44