Finding the Fourth Proportional to 1,039.82, 1,566.78 and 861.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.82 : 1,566.78 = 861.21 : x
2. Step 2: Convert to fraction form
   1,039.82/1,566.78 = 861.21/x
3. Step 3: Cross multiply
   1,039.82x = 1,566.78 × 861.21
4. Step 4: Simplify right side
   1,039.82x = 1,349,326.60
5. Step 5: Solve for x
   x = 1,349,326.60/1,039.82
6. Step 6: Final answer
   x = 1,297.66