Finding the Fourth Proportional to 1,064.49, 1,469.03 and 644.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,064.49 : 1,469.03 = 644.78 : x
2. Step 2: Convert to fraction form
   1,064.49/1,469.03 = 644.78/x
3. Step 3: Cross multiply
   1,064.49x = 1,469.03 × 644.78
4. Step 4: Simplify right side
   1,064.49x = 947,190.59
5. Step 5: Solve for x
   x = 947,190.59/1,064.49
6. Step 6: Final answer
   x = 889.81