Finding the Fourth Proportional to 3,380.89, 5,070.72 and 915.91

Step by Step Solution

1. Step 1: Write the proportion equation
   3,380.89 : 5,070.72 = 915.91 : x
2. Step 2: Convert to fraction form
   3,380.89/5,070.72 = 915.91/x
3. Step 3: Cross multiply
   3,380.89x = 5,070.72 × 915.91
4. Step 4: Simplify right side
   3,380.89x = 4,644,318.58
5. Step 5: Solve for x
   x = 4,644,318.58/3,380.89
6. Step 6: Final answer
   x = 1,373.70