Finding the Fourth Proportional to 1,136.72, 1,568.52 and 639.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,136.72 : 1,568.52 = 639.24 : x
2. Step 2: Convert to fraction form
   1,136.72/1,568.52 = 639.24/x
3. Step 3: Cross multiply
   1,136.72x = 1,568.52 × 639.24
4. Step 4: Simplify right side
   1,136.72x = 1,002,660.72
5. Step 5: Solve for x
   x = 1,002,660.72/1,136.72
6. Step 6: Final answer
   x = 882.06