Finding the Fourth Proportional to 1,398.72, 1,931.12 and 956.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.72 : 1,931.12 = 956.96 : x
2. Step 2: Convert to fraction form
   1,398.72/1,931.12 = 956.96/x
3. Step 3: Cross multiply
   1,398.72x = 1,931.12 × 956.96
4. Step 4: Simplify right side
   1,398.72x = 1,848,004.60
5. Step 5: Solve for x
   x = 1,848,004.60/1,398.72
6. Step 6: Final answer
   x = 1,321.21