Finding the Fourth Proportional to 1,439.25, 1,986.19 and 915.99

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.25 : 1,986.19 = 915.99 : x
2. Step 2: Convert to fraction form
   1,439.25/1,986.19 = 915.99/x
3. Step 3: Cross multiply
   1,439.25x = 1,986.19 × 915.99
4. Step 4: Simplify right side
   1,439.25x = 1,819,327.89
5. Step 5: Solve for x
   x = 1,819,327.89/1,439.25
6. Step 6: Final answer
   x = 1,264.08