Finding the Fourth Proportional to 1,369.57, 1,890.02 and 780.11

Step by Step Solution

1. Step 1: Write the proportion equation
   1,369.57 : 1,890.02 = 780.11 : x
2. Step 2: Convert to fraction form
   1,369.57/1,890.02 = 780.11/x
3. Step 3: Cross multiply
   1,369.57x = 1,890.02 × 780.11
4. Step 4: Simplify right side
   1,369.57x = 1,474,423.50
5. Step 5: Solve for x
   x = 1,474,423.50/1,369.57
6. Step 6: Final answer
   x = 1,076.56