Finding the Fourth Proportional to 1,009.56, 1,393.40 and 636.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,009.56 : 1,393.40 = 636.28 : x
2. Step 2: Convert to fraction form
   1,009.56/1,393.40 = 636.28/x
3. Step 3: Cross multiply
   1,009.56x = 1,393.40 × 636.28
4. Step 4: Simplify right side
   1,009.56x = 886,592.55
5. Step 5: Solve for x
   x = 886,592.55/1,009.56
6. Step 6: Final answer
   x = 878.20