Finding the Fourth Proportional to 1,136.69, 1,568.57 and 639.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,136.69 : 1,568.57 = 639.37 : x
2. Step 2: Convert to fraction form
   1,136.69/1,568.57 = 639.37/x
3. Step 3: Cross multiply
   1,136.69x = 1,568.57 × 639.37
4. Step 4: Simplify right side
   1,136.69x = 1,002,889.48
5. Step 5: Solve for x
   x = 1,002,889.48/1,136.69
6. Step 6: Final answer
   x = 882.29