Finding the Fourth Proportional to 2,647.18, 3,971.40 and 915.82

Step by Step Solution

1. Step 1: Write the proportion equation
   2,647.18 : 3,971.40 = 915.82 : x
2. Step 2: Convert to fraction form
   2,647.18/3,971.40 = 915.82/x
3. Step 3: Cross multiply
   2,647.18x = 3,971.40 × 915.82
4. Step 4: Simplify right side
   2,647.18x = 3,637,087.55
5. Step 5: Solve for x
   x = 3,637,087.55/2,647.18
6. Step 6: Final answer
   x = 1,373.95