Finding the Fourth Proportional to 1,880.24, 2,821.61 and 839.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,880.24 : 2,821.61 = 839.89 : x
2. Step 2: Convert to fraction form
   1,880.24/2,821.61 = 839.89/x
3. Step 3: Cross multiply
   1,880.24x = 2,821.61 × 839.89
4. Step 4: Simplify right side
   1,880.24x = 2,369,837.82
5. Step 5: Solve for x
   x = 2,369,837.82/1,880.24
6. Step 6: Final answer
   x = 1,260.39