Finding the Fourth Proportional to 1,380.31, 2,065.21 and 933.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.31 : 2,065.21 = 933.79 : x
2. Step 2: Convert to fraction form
   1,380.31/2,065.21 = 933.79/x
3. Step 3: Cross multiply
   1,380.31x = 2,065.21 × 933.79
4. Step 4: Simplify right side
   1,380.31x = 1,928,467.78
5. Step 5: Solve for x
   x = 1,928,467.78/1,380.31
6. Step 6: Final answer
   x = 1,397.13