Finding the Fourth Proportional to 1,017.74, 1,404.24 and 644.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,017.74 : 1,404.24 = 644.06 : x
2. Step 2: Convert to fraction form
   1,017.74/1,404.24 = 644.06/x
3. Step 3: Cross multiply
   1,017.74x = 1,404.24 × 644.06
4. Step 4: Simplify right side
   1,017.74x = 904,414.81
5. Step 5: Solve for x
   x = 904,414.81/1,017.74
6. Step 6: Final answer
   x = 888.65