Finding the Fourth Proportional to 1,111.24, 1,665.42 and 721.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.24 : 1,665.42 = 721.18 : x
2. Step 2: Convert to fraction form
   1,111.24/1,665.42 = 721.18/x
3. Step 3: Cross multiply
   1,111.24x = 1,665.42 × 721.18
4. Step 4: Simplify right side
   1,111.24x = 1,201,067.60
5. Step 5: Solve for x
   x = 1,201,067.60/1,111.24
6. Step 6: Final answer
   x = 1,080.84