Finding the Fourth Proportional to 1,116.61, 1,672.75 and 859.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.61 : 1,672.75 = 859.57 : x
2. Step 2: Convert to fraction form
   1,116.61/1,672.75 = 859.57/x
3. Step 3: Cross multiply
   1,116.61x = 1,672.75 × 859.57
4. Step 4: Simplify right side
   1,116.61x = 1,437,845.72
5. Step 5: Solve for x
   x = 1,437,845.72/1,116.61
6. Step 6: Final answer
   x = 1,287.69