Finding the Fourth Proportional to 1,369.41, 1,889.81 and 780.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,369.41 : 1,889.81 = 780.09 : x
2. Step 2: Convert to fraction form
   1,369.41/1,889.81 = 780.09/x
3. Step 3: Cross multiply
   1,369.41x = 1,889.81 × 780.09
4. Step 4: Simplify right side
   1,369.41x = 1,474,221.88
5. Step 5: Solve for x
   x = 1,474,221.88/1,369.41
6. Step 6: Final answer
   x = 1,076.54