Finding the Fourth Proportional to 1,116.25, 1,541.94 and 870.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.25 : 1,541.94 = 870.78 : x
2. Step 2: Convert to fraction form
   1,116.25/1,541.94 = 870.78/x
3. Step 3: Cross multiply
   1,116.25x = 1,541.94 × 870.78
4. Step 4: Simplify right side
   1,116.25x = 1,342,693.03
5. Step 5: Solve for x
   x = 1,342,693.03/1,116.25
6. Step 6: Final answer
   x = 1,202.86