Finding the Fourth Proportional to 2,808.47, 4,212.61 and 860.63

Step by Step Solution

1. Step 1: Write the proportion equation
   2,808.47 : 4,212.61 = 860.63 : x
2. Step 2: Convert to fraction form
   2,808.47/4,212.61 = 860.63/x
3. Step 3: Cross multiply
   2,808.47x = 4,212.61 × 860.63
4. Step 4: Simplify right side
   2,808.47x = 3,625,475.33
5. Step 5: Solve for x
   x = 3,625,475.33/2,808.47
6. Step 6: Final answer
   x = 1,290.91