Finding the Fourth Proportional to 2,647.28, 3,970.02 and 915.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,647.28 : 3,970.02 = 915.50 : x
2. Step 2: Convert to fraction form
   2,647.28/3,970.02 = 915.50/x
3. Step 3: Cross multiply
   2,647.28x = 3,970.02 × 915.50
4. Step 4: Simplify right side
   2,647.28x = 3,634,553.31
5. Step 5: Solve for x
   x = 3,634,553.31/2,647.28
6. Step 6: Final answer
   x = 1,372.94