Finding the Fourth Proportional to 931.50, 1,389.02 and 864.54

Step by Step Solution

1. Step 1: Write the proportion equation
   931.50 : 1,389.02 = 864.54 : x
2. Step 2: Convert to fraction form
   931.50/1,389.02 = 864.54/x
3. Step 3: Cross multiply
   931.50x = 1,389.02 × 864.54
4. Step 4: Simplify right side
   931.50x = 1,200,859.03
5. Step 5: Solve for x
   x = 1,200,859.03/931.50
6. Step 6: Final answer
   x = 1,289.17