Finding the Fourth Proportional to 2,147.85, 3,221.37 and 915.37

Step by Step Solution

1. Step 1: Write the proportion equation
   2,147.85 : 3,221.37 = 915.37 : x
2. Step 2: Convert to fraction form
   2,147.85/3,221.37 = 915.37/x
3. Step 3: Cross multiply
   2,147.85x = 3,221.37 × 915.37
4. Step 4: Simplify right side
   2,147.85x = 2,948,737.40
5. Step 5: Solve for x
   x = 2,948,737.40/2,147.85
6. Step 6: Final answer
   x = 1,372.88