Finding the Fourth Proportional to 1,393.29, 1,922.17 and 921.43

Step by Step Solution

1. Step 1: Write the proportion equation
   1,393.29 : 1,922.17 = 921.43 : x
2. Step 2: Convert to fraction form
   1,393.29/1,922.17 = 921.43/x
3. Step 3: Cross multiply
   1,393.29x = 1,922.17 × 921.43
4. Step 4: Simplify right side
   1,393.29x = 1,771,145.10
5. Step 5: Solve for x
   x = 1,771,145.10/1,393.29
6. Step 6: Final answer
   x = 1,271.20