Finding the Fourth Proportional to 1,137.69, 1,702.71 and 815.22

Step by Step Solution

1. Step 1: Write the proportion equation
   1,137.69 : 1,702.71 = 815.22 : x
2. Step 2: Convert to fraction form
   1,137.69/1,702.71 = 815.22/x
3. Step 3: Cross multiply
   1,137.69x = 1,702.71 × 815.22
4. Step 4: Simplify right side
   1,137.69x = 1,388,083.25
5. Step 5: Solve for x
   x = 1,388,083.25/1,137.69
6. Step 6: Final answer
   x = 1,220.09