Finding the Fourth Proportional to 2,391.32, 3,587.90 and 931.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,391.32 : 3,587.90 = 931.50 : x
2. Step 2: Convert to fraction form
   2,391.32/3,587.90 = 931.50/x
3. Step 3: Cross multiply
   2,391.32x = 3,587.90 × 931.50
4. Step 4: Simplify right side
   2,391.32x = 3,342,128.85
5. Step 5: Solve for x
   x = 3,342,128.85/2,391.32
6. Step 6: Final answer
   x = 1,397.61