Finding the Fourth Proportional to 2,587.34, 3,881.16 and 639.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,587.34 : 3,881.16 = 639.56 : x
2. Step 2: Convert to fraction form
   2,587.34/3,881.16 = 639.56/x
3. Step 3: Cross multiply
   2,587.34x = 3,881.16 × 639.56
4. Step 4: Simplify right side
   2,587.34x = 2,482,234.69
5. Step 5: Solve for x
   x = 2,482,234.69/2,587.34
6. Step 6: Final answer
   x = 959.38