Finding the Fourth Proportional to 1,391.31, 1,919.93 and 761.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.31 : 1,919.93 = 761.83 : x
2. Step 2: Convert to fraction form
   1,391.31/1,919.93 = 761.83/x
3. Step 3: Cross multiply
   1,391.31x = 1,919.93 × 761.83
4. Step 4: Simplify right side
   1,391.31x = 1,462,657.38
5. Step 5: Solve for x
   x = 1,462,657.38/1,391.31
6. Step 6: Final answer
   x = 1,051.28