Finding the Fourth Proportional to 1,389.40, 1,917.42 and 759.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.40 : 1,917.42 = 759.89 : x
2. Step 2: Convert to fraction form
   1,389.40/1,917.42 = 759.89/x
3. Step 3: Cross multiply
   1,389.40x = 1,917.42 × 759.89
4. Step 4: Simplify right side
   1,389.40x = 1,457,018.24
5. Step 5: Solve for x
   x = 1,457,018.24/1,389.40
6. Step 6: Final answer
   x = 1,048.67