Finding the Fourth Proportional to 1,369.58, 1,890.03 and 780.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,369.58 : 1,890.03 = 780.10 : x
2. Step 2: Convert to fraction form
   1,369.58/1,890.03 = 780.10/x
3. Step 3: Cross multiply
   1,369.58x = 1,890.03 × 780.10
4. Step 4: Simplify right side
   1,369.58x = 1,474,410.60
5. Step 5: Solve for x
   x = 1,474,410.60/1,369.58
6. Step 6: Final answer
   x = 1,076.55