Finding the Fourth Proportional to 1,290.03, 1,780.71 and 766.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.03 : 1,780.71 = 766.07 : x
2. Step 2: Convert to fraction form
   1,290.03/1,780.71 = 766.07/x
3. Step 3: Cross multiply
   1,290.03x = 1,780.71 × 766.07
4. Step 4: Simplify right side
   1,290.03x = 1,364,135.78
5. Step 5: Solve for x
   x = 1,364,135.78/1,290.03
6. Step 6: Final answer
   x = 1,057.45