Finding the Fourth Proportional to 1,405.48, 2,109.18 and 721.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.48 : 2,109.18 = 721.96 : x
2. Step 2: Convert to fraction form
   1,405.48/2,109.18 = 721.96/x
3. Step 3: Cross multiply
   1,405.48x = 2,109.18 × 721.96
4. Step 4: Simplify right side
   1,405.48x = 1,522,743.59
5. Step 5: Solve for x
   x = 1,522,743.59/1,405.48
6. Step 6: Final answer
   x = 1,083.43