Finding the Fourth Proportional to 1,105.20, 1,656.72 and 673.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.20 : 1,656.72 = 673.20 : x
2. Step 2: Convert to fraction form
   1,105.20/1,656.72 = 673.20/x
3. Step 3: Cross multiply
   1,105.20x = 1,656.72 × 673.20
4. Step 4: Simplify right side
   1,105.20x = 1,115,303.90
5. Step 5: Solve for x
   x = 1,115,303.90/1,105.20
6. Step 6: Final answer
   x = 1,009.14