Finding the Fourth Proportional to 2,870.10, 3,959.28 and 1,689.96

Step by Step Solution

1. Step 1: Write the proportion equation
   2,870.10 : 3,959.28 = 1,689.96 : x
2. Step 2: Convert to fraction form
   2,870.10/3,959.28 = 1,689.96/x
3. Step 3: Cross multiply
   2,870.10x = 3,959.28 × 1,689.96
4. Step 4: Simplify right side
   2,870.10x = 6,691,024.83
5. Step 5: Solve for x
   x = 6,691,024.83/2,870.10
6. Step 6: Final answer
   x = 2,331.29