Finding the Fourth Proportional to 1,392.31, 1,919.05 and 1,111.65

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.31 : 1,919.05 = 1,111.65 : x
2. Step 2: Convert to fraction form
   1,392.31/1,919.05 = 1,111.65/x
3. Step 3: Cross multiply
   1,392.31x = 1,919.05 × 1,111.65
4. Step 4: Simplify right side
   1,392.31x = 2,133,311.93
5. Step 5: Solve for x
   x = 2,133,311.93/1,392.31
6. Step 6: Final answer
   x = 1,532.21