Finding the Fourth Proportional to 1,380.78, 1,904.51 and 937.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.78 : 1,904.51 = 937.91 : x
2. Step 2: Convert to fraction form
   1,380.78/1,904.51 = 937.91/x
3. Step 3: Cross multiply
   1,380.78x = 1,904.51 × 937.91
4. Step 4: Simplify right side
   1,380.78x = 1,786,266.08
5. Step 5: Solve for x
   x = 1,786,266.08/1,380.78
6. Step 6: Final answer
   x = 1,293.66