Finding the Fourth Proportional to 1,391.61, 1,921.17 and 948.75

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.61 : 1,921.17 = 948.75 : x
2. Step 2: Convert to fraction form
   1,391.61/1,921.17 = 948.75/x
3. Step 3: Cross multiply
   1,391.61x = 1,921.17 × 948.75
4. Step 4: Simplify right side
   1,391.61x = 1,822,710.04
5. Step 5: Solve for x
   x = 1,822,710.04/1,391.61
6. Step 6: Final answer
   x = 1,309.79