Finding the Fourth Proportional to 1,485.20, 2,227.37 and 860.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,485.20 : 2,227.37 = 860.69 : x
2. Step 2: Convert to fraction form
   1,485.20/2,227.37 = 860.69/x
3. Step 3: Cross multiply
   1,485.20x = 2,227.37 × 860.69
4. Step 4: Simplify right side
   1,485.20x = 1,917,059.65
5. Step 5: Solve for x
   x = 1,917,059.65/1,485.20
6. Step 6: Final answer
   x = 1,290.78