Finding the Fourth Proportional to 1,136.72, 1,568.29 and 639.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,136.72 : 1,568.29 = 639.25 : x
2. Step 2: Convert to fraction form
   1,136.72/1,568.29 = 639.25/x
3. Step 3: Cross multiply
   1,136.72x = 1,568.29 × 639.25
4. Step 4: Simplify right side
   1,136.72x = 1,002,532.09
5. Step 5: Solve for x
   x = 1,002,532.09/1,136.72
6. Step 6: Final answer
   x = 881.95