Finding the Fourth Proportional to 1,919.75, 2,648.25 and 1,290.35

Step by Step Solution

1. Step 1: Write the proportion equation
   1,919.75 : 2,648.25 = 1,290.35 : x
2. Step 2: Convert to fraction form
   1,919.75/2,648.25 = 1,290.35/x
3. Step 3: Cross multiply
   1,919.75x = 2,648.25 × 1,290.35
4. Step 4: Simplify right side
   1,919.75x = 3,417,156.15
5. Step 5: Solve for x
   x = 3,417,156.15/1,919.75
6. Step 6: Final answer
   x = 1,780.01