Finding the Fourth Proportional to 1,369.95, 1,890.34 and 780.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,369.95 : 1,890.34 = 780.37 : x
2. Step 2: Convert to fraction form
   1,369.95/1,890.34 = 780.37/x
3. Step 3: Cross multiply
   1,369.95x = 1,890.34 × 780.37
4. Step 4: Simplify right side
   1,369.95x = 1,475,157.95
5. Step 5: Solve for x
   x = 1,475,157.95/1,369.95
6. Step 6: Final answer
   x = 1,076.80