Finding the Fourth Proportional to 1,928.78, 2,661.70 and 1,089.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,928.78 : 2,661.70 = 1,089.47 : x
2. Step 2: Convert to fraction form
   1,928.78/2,661.70 = 1,089.47/x
3. Step 3: Cross multiply
   1,928.78x = 2,661.70 × 1,089.47
4. Step 4: Simplify right side
   1,928.78x = 2,899,842.30
5. Step 5: Solve for x
   x = 2,899,842.30/1,928.78
6. Step 6: Final answer
   x = 1,503.46