Finding the Fourth Proportional to 1,387.94, 1,915.04 and 828.23

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.94 : 1,915.04 = 828.23 : x
2. Step 2: Convert to fraction form
   1,387.94/1,915.04 = 828.23/x
3. Step 3: Cross multiply
   1,387.94x = 1,915.04 × 828.23
4. Step 4: Simplify right side
   1,387.94x = 1,586,086.07
5. Step 5: Solve for x
   x = 1,586,086.07/1,387.94
6. Step 6: Final answer
   x = 1,142.77