Finding the Fourth Proportional to 1,290.02, 1,780.25 and 766.35

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.02 : 1,780.25 = 766.35 : x
2. Step 2: Convert to fraction form
   1,290.02/1,780.25 = 766.35/x
3. Step 3: Cross multiply
   1,290.02x = 1,780.25 × 766.35
4. Step 4: Simplify right side
   1,290.02x = 1,364,290.76
5. Step 5: Solve for x
   x = 1,364,290.76/1,290.02
6. Step 6: Final answer
   x = 1,057.58