Finding the Fourth Proportional to 1,369.55, 1,890.12 and 838.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,369.55 : 1,890.12 = 838.78 : x
2. Step 2: Convert to fraction form
   1,369.55/1,890.12 = 838.78/x
3. Step 3: Cross multiply
   1,369.55x = 1,890.12 × 838.78
4. Step 4: Simplify right side
   1,369.55x = 1,585,394.85
5. Step 5: Solve for x
   x = 1,585,394.85/1,369.55
6. Step 6: Final answer
   x = 1,157.60