Finding the Fourth Proportional to 1,561.31, 2,154.71 and 862.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.31 : 2,154.71 = 862.69 : x
2. Step 2: Convert to fraction form
   1,561.31/2,154.71 = 862.69/x
3. Step 3: Cross multiply
   1,561.31x = 2,154.71 × 862.69
4. Step 4: Simplify right side
   1,561.31x = 1,858,843.54
5. Step 5: Solve for x
   x = 1,858,843.54/1,561.31
6. Step 6: Final answer
   x = 1,190.56