Finding the Fourth Proportional to 1,391.46, 1,921.92 and 1,017.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.46 : 1,921.92 = 1,017.90 : x
2. Step 2: Convert to fraction form
   1,391.46/1,921.92 = 1,017.90/x
3. Step 3: Cross multiply
   1,391.46x = 1,921.92 × 1,017.90
4. Step 4: Simplify right side
   1,391.46x = 1,956,322.37
5. Step 5: Solve for x
   x = 1,956,322.37/1,391.46
6. Step 6: Final answer
   x = 1,405.95