Finding the Fourth Proportional to 1,428.72, 2,139.60 and 733.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.72 : 2,139.60 = 733.20 : x
2. Step 2: Convert to fraction form
   1,428.72/2,139.60 = 733.20/x
3. Step 3: Cross multiply
   1,428.72x = 2,139.60 × 733.20
4. Step 4: Simplify right side
   1,428.72x = 1,568,754.72
5. Step 5: Solve for x
   x = 1,568,754.72/1,428.72
6. Step 6: Final answer
   x = 1,098.01