Finding the Fourth Proportional to 2,086.79, 2,880.50 and 1,290.73

Step by Step Solution

1. Step 1: Write the proportion equation
   2,086.79 : 2,880.50 = 1,290.73 : x
2. Step 2: Convert to fraction form
   2,086.79/2,880.50 = 1,290.73/x
3. Step 3: Cross multiply
   2,086.79x = 2,880.50 × 1,290.73
4. Step 4: Simplify right side
   2,086.79x = 3,717,942.30
5. Step 5: Solve for x
   x = 3,717,942.30/2,086.79
6. Step 6: Final answer
   x = 1,781.66