Finding the Fourth Proportional to 1,284.79, 1,772.17 and 787.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,284.79 : 1,772.17 = 787.25 : x
2. Step 2: Convert to fraction form
   1,284.79/1,772.17 = 787.25/x
3. Step 3: Cross multiply
   1,284.79x = 1,772.17 × 787.25
4. Step 4: Simplify right side
   1,284.79x = 1,395,140.83
5. Step 5: Solve for x
   x = 1,395,140.83/1,284.79
6. Step 6: Final answer
   x = 1,085.89