Finding the Fourth Proportional to 1,569.69, 2,166.15 and 861.51

Step by Step Solution

1. Step 1: Write the proportion equation
   1,569.69 : 2,166.15 = 861.51 : x
2. Step 2: Convert to fraction form
   1,569.69/2,166.15 = 861.51/x
3. Step 3: Cross multiply
   1,569.69x = 2,166.15 × 861.51
4. Step 4: Simplify right side
   1,569.69x = 1,866,159.89
5. Step 5: Solve for x
   x = 1,866,159.89/1,569.69
6. Step 6: Final answer
   x = 1,188.87