Finding the Fourth Proportional to 2,160.69, 3,240.36 and 928.05

Step by Step Solution

1. Step 1: Write the proportion equation
   2,160.69 : 3,240.36 = 928.05 : x
2. Step 2: Convert to fraction form
   2,160.69/3,240.36 = 928.05/x
3. Step 3: Cross multiply
   2,160.69x = 3,240.36 × 928.05
4. Step 4: Simplify right side
   2,160.69x = 3,007,216.10
5. Step 5: Solve for x
   x = 3,007,216.10/2,160.69
6. Step 6: Final answer
   x = 1,391.79