Finding the Fourth Proportional to 2,621.91, 3,932.96 and 890.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,621.91 : 3,932.96 = 890.31 : x
2. Step 2: Convert to fraction form
   2,621.91/3,932.96 = 890.31/x
3. Step 3: Cross multiply
   2,621.91x = 3,932.96 × 890.31
4. Step 4: Simplify right side
   2,621.91x = 3,501,553.62
5. Step 5: Solve for x
   x = 3,501,553.62/2,621.91
6. Step 6: Final answer
   x = 1,335.50