Finding the Fourth Proportional to 1,386.75, 1,913.72 and 757.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386.75 : 1,913.72 = 757.28 : x
2. Step 2: Convert to fraction form
   1,386.75/1,913.72 = 757.28/x
3. Step 3: Cross multiply
   1,386.75x = 1,913.72 × 757.28
4. Step 4: Simplify right side
   1,386.75x = 1,449,221.88
5. Step 5: Solve for x
   x = 1,449,221.88/1,386.75
6. Step 6: Final answer
   x = 1,045.05