Finding the Fourth Proportional to 1,136.51, 1,568.55 and 639.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,136.51 : 1,568.55 = 639.18 : x
2. Step 2: Convert to fraction form
   1,136.51/1,568.55 = 639.18/x
3. Step 3: Cross multiply
   1,136.51x = 1,568.55 × 639.18
4. Step 4: Simplify right side
   1,136.51x = 1,002,582.59
5. Step 5: Solve for x
   x = 1,002,582.59/1,136.51
6. Step 6: Final answer
   x = 882.16