Finding the Fourth Proportional to 1,308.55, 1,806.69 and 915.70

Step by Step Solution

1. Step 1: Write the proportion equation
   1,308.55 : 1,806.69 = 915.70 : x
2. Step 2: Convert to fraction form
   1,308.55/1,806.69 = 915.70/x
3. Step 3: Cross multiply
   1,308.55x = 1,806.69 × 915.70
4. Step 4: Simplify right side
   1,308.55x = 1,654,386.03
5. Step 5: Solve for x
   x = 1,654,386.03/1,308.55
6. Step 6: Final answer
   x = 1,264.29