Finding the Fourth Proportional to 1,369.78, 1,889.83 and 779.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,369.78 : 1,889.83 = 779.90 : x
2. Step 2: Convert to fraction form
   1,369.78/1,889.83 = 779.90/x
3. Step 3: Cross multiply
   1,369.78x = 1,889.83 × 779.90
4. Step 4: Simplify right side
   1,369.78x = 1,473,869.94
5. Step 5: Solve for x
   x = 1,473,869.94/1,369.78
6. Step 6: Final answer
   x = 1,075.99