Finding the Fourth Proportional to 2,020.78, 2,788.71 and 1,224.13

Step by Step Solution

1. Step 1: Write the proportion equation
   2,020.78 : 2,788.71 = 1,224.13 : x
2. Step 2: Convert to fraction form
   2,020.78/2,788.71 = 1,224.13/x
3. Step 3: Cross multiply
   2,020.78x = 2,788.71 × 1,224.13
4. Step 4: Simplify right side
   2,020.78x = 3,413,744.12
5. Step 5: Solve for x
   x = 3,413,744.12/2,020.78
6. Step 6: Final answer
   x = 1,689.32