Finding the Fourth Proportional to 1,136.77, 1,568.59 and 639.29

Step by Step Solution

1. Step 1: Write the proportion equation
   1,136.77 : 1,568.59 = 639.29 : x
2. Step 2: Convert to fraction form
   1,136.77/1,568.59 = 639.29/x
3. Step 3: Cross multiply
   1,136.77x = 1,568.59 × 639.29
4. Step 4: Simplify right side
   1,136.77x = 1,002,786.22
5. Step 5: Solve for x
   x = 1,002,786.22/1,136.77
6. Step 6: Final answer
   x = 882.14