Finding the Fourth Proportional to 1,002.56, 1,383.78 and 648.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,002.56 : 1,383.78 = 648.88 : x
2. Step 2: Convert to fraction form
   1,002.56/1,383.78 = 648.88/x
3. Step 3: Cross multiply
   1,002.56x = 1,383.78 × 648.88
4. Step 4: Simplify right side
   1,002.56x = 897,900.25
5. Step 5: Solve for x
   x = 897,900.25/1,002.56
6. Step 6: Final answer
   x = 895.61