Finding the Fourth Proportional to 2,020.80, 2,783.70 and 1,689.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,020.80 : 2,783.70 = 1,689.12 : x
2. Step 2: Convert to fraction form
   2,020.80/2,783.70 = 1,689.12/x
3. Step 3: Cross multiply
   2,020.80x = 2,783.70 × 1,689.12
4. Step 4: Simplify right side
   2,020.80x = 4,702,003.34
5. Step 5: Solve for x
   x = 4,702,003.34/2,020.80
6. Step 6: Final answer
   x = 2,326.80