Finding the Fourth Proportional to 2,820.87, 3,886.32 and 2,689.65

Step by Step Solution

1. Step 1: Write the proportion equation
   2,820.87 : 3,886.32 = 2,689.65 : x
2. Step 2: Convert to fraction form
   2,820.87/3,886.32 = 2,689.65/x
3. Step 3: Cross multiply
   2,820.87x = 3,886.32 × 2,689.65
4. Step 4: Simplify right side
   2,820.87x = 10,452,840.59
5. Step 5: Solve for x
   x = 10,452,840.59/2,820.87
6. Step 6: Final answer
   x = 3,705.54