Finding the Fourth Proportional to 1,136.37, 1,568.16 and 639.02

Step by Step Solution

1. Step 1: Write the proportion equation
   1,136.37 : 1,568.16 = 639.02 : x
2. Step 2: Convert to fraction form
   1,136.37/1,568.16 = 639.02/x
3. Step 3: Cross multiply
   1,136.37x = 1,568.16 × 639.02
4. Step 4: Simplify right side
   1,136.37x = 1,002,077.76
5. Step 5: Solve for x
   x = 1,002,077.76/1,136.37
6. Step 6: Final answer
   x = 881.82