Finding the Fourth Proportional to 1,401.80, 1,934.58 and 780.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.80 : 1,934.58 = 780.68 : x
2. Step 2: Convert to fraction form
   1,401.80/1,934.58 = 780.68/x
3. Step 3: Cross multiply
   1,401.80x = 1,934.58 × 780.68
4. Step 4: Simplify right side
   1,401.80x = 1,510,287.91
5. Step 5: Solve for x
   x = 1,510,287.91/1,401.80
6. Step 6: Final answer
   x = 1,077.39