Finding the Fourth Proportional to 1,136.52, 1,568.34 and 639.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,136.52 : 1,568.34 = 639.15 : x
2. Step 2: Convert to fraction form
   1,136.52/1,568.34 = 639.15/x
3. Step 3: Cross multiply
   1,136.52x = 1,568.34 × 639.15
4. Step 4: Simplify right side
   1,136.52x = 1,002,404.51
5. Step 5: Solve for x
   x = 1,002,404.51/1,136.52
6. Step 6: Final answer
   x = 881.99