Finding the Fourth Proportional to 2,085.54, 3,128.94 and 915.06

Step by Step Solution

1. Step 1: Write the proportion equation
   2,085.54 : 3,128.94 = 915.06 : x
2. Step 2: Convert to fraction form
   2,085.54/3,128.94 = 915.06/x
3. Step 3: Cross multiply
   2,085.54x = 3,128.94 × 915.06
4. Step 4: Simplify right side
   2,085.54x = 2,863,167.84
5. Step 5: Solve for x
   x = 2,863,167.84/2,085.54
6. Step 6: Final answer
   x = 1,372.87