Finding the Fourth Proportional to 1,391.64, 1,920.48 and 762.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.64 : 1,920.48 = 762.15 : x
2. Step 2: Convert to fraction form
   1,391.64/1,920.48 = 762.15/x
3. Step 3: Cross multiply
   1,391.64x = 1,920.48 × 762.15
4. Step 4: Simplify right side
   1,391.64x = 1,463,693.83
5. Step 5: Solve for x
   x = 1,463,693.83/1,391.64
6. Step 6: Final answer
   x = 1,051.78