Finding the Fourth Proportional to 1,105.12, 1,656.16 and 860.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.12 : 1,656.16 = 860.52 : x
2. Step 2: Convert to fraction form
   1,105.12/1,656.16 = 860.52/x
3. Step 3: Cross multiply
   1,105.12x = 1,656.16 × 860.52
4. Step 4: Simplify right side
   1,105.12x = 1,425,158.80
5. Step 5: Solve for x
   x = 1,425,158.80/1,105.12
6. Step 6: Final answer
   x = 1,289.60