Finding the Fourth Proportional to 1,401.20, 1,933.65 and 780.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.20 : 1,933.65 = 780.20 : x
2. Step 2: Convert to fraction form
   1,401.20/1,933.65 = 780.20/x
3. Step 3: Cross multiply
   1,401.20x = 1,933.65 × 780.20
4. Step 4: Simplify right side
   1,401.20x = 1,508,624.06
5. Step 5: Solve for x
   x = 1,508,624.06/1,401.20
6. Step 6: Final answer
   x = 1,076.67