Finding the Fourth Proportional to 1,073.80, 1,610.72 and 859.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,073.80 : 1,610.72 = 859.96 : x
2. Step 2: Convert to fraction form
   1,073.80/1,610.72 = 859.96/x
3. Step 3: Cross multiply
   1,073.80x = 1,610.72 × 859.96
4. Step 4: Simplify right side
   1,073.80x = 1,385,154.77
5. Step 5: Solve for x
   x = 1,385,154.77/1,073.80
6. Step 6: Final answer
   x = 1,289.96