Finding the Fourth Proportional to 1,139.82, 1,572.31 and 720.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.82 : 1,572.31 = 720.24 : x
2. Step 2: Convert to fraction form
   1,139.82/1,572.31 = 720.24/x
3. Step 3: Cross multiply
   1,139.82x = 1,572.31 × 720.24
4. Step 4: Simplify right side
   1,139.82x = 1,132,444.40
5. Step 5: Solve for x
   x = 1,132,444.40/1,139.82
6. Step 6: Final answer
   x = 993.53