Finding the Fourth Proportional to 1,401.68, 1,934.24 and 780.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.68 : 1,934.24 = 780.72 : x
2. Step 2: Convert to fraction form
   1,401.68/1,934.24 = 780.72/x
3. Step 3: Cross multiply
   1,401.68x = 1,934.24 × 780.72
4. Step 4: Simplify right side
   1,401.68x = 1,510,099.85
5. Step 5: Solve for x
   x = 1,510,099.85/1,401.68
6. Step 6: Final answer
   x = 1,077.35