Finding the Fourth Proportional to 1,290.66, 1,781.37 and 766.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.66 : 1,781.37 = 766.59 : x
2. Step 2: Convert to fraction form
   1,290.66/1,781.37 = 766.59/x
3. Step 3: Cross multiply
   1,290.66x = 1,781.37 × 766.59
4. Step 4: Simplify right side
   1,290.66x = 1,365,580.43
5. Step 5: Solve for x
   x = 1,365,580.43/1,290.66
6. Step 6: Final answer
   x = 1,058.05