Finding the Fourth Proportional to 2,648.21, 3,972.27 and 916.79

Step by Step Solution

1. Step 1: Write the proportion equation
   2,648.21 : 3,972.27 = 916.79 : x
2. Step 2: Convert to fraction form
   2,648.21/3,972.27 = 916.79/x
3. Step 3: Cross multiply
   2,648.21x = 3,972.27 × 916.79
4. Step 4: Simplify right side
   2,648.21x = 3,641,737.41
5. Step 5: Solve for x
   x = 3,641,737.41/2,648.21
6. Step 6: Final answer
   x = 1,375.17