Finding the Fourth Proportional to 1,919.75, 2,650.78 and 1,290.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,919.75 : 2,650.78 = 1,290.83 : x
2. Step 2: Convert to fraction form
   1,919.75/2,650.78 = 1,290.83/x
3. Step 3: Cross multiply
   1,919.75x = 2,650.78 × 1,290.83
4. Step 4: Simplify right side
   1,919.75x = 3,421,696.49
5. Step 5: Solve for x
   x = 3,421,696.49/1,919.75
6. Step 6: Final answer
   x = 1,782.37