Finding the Fourth Proportional to 1,927.40, 2,658.78 and 1,290.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,927.40 : 2,658.78 = 1,290.42 : x
2. Step 2: Convert to fraction form
   1,927.40/2,658.78 = 1,290.42/x
3. Step 3: Cross multiply
   1,927.40x = 2,658.78 × 1,290.42
4. Step 4: Simplify right side
   1,927.40x = 3,430,942.89
5. Step 5: Solve for x
   x = 3,430,942.89/1,927.40
6. Step 6: Final answer
   x = 1,780.09