Finding the Fourth Proportional to 2,986.72, 4,480.31 and 906.89

Step by Step Solution

1. Step 1: Write the proportion equation
   2,986.72 : 4,480.31 = 906.89 : x
2. Step 2: Convert to fraction form
   2,986.72/4,480.31 = 906.89/x
3. Step 3: Cross multiply
   2,986.72x = 4,480.31 × 906.89
4. Step 4: Simplify right side
   2,986.72x = 4,063,128.20
5. Step 5: Solve for x
   x = 4,063,128.20/2,986.72
6. Step 6: Final answer
   x = 1,360.40