Finding the Fourth Proportional to 2,641.65, 3,980.61 and 2,189.57

Step by Step Solution

1. Step 1: Write the proportion equation
   2,641.65 : 3,980.61 = 2,189.57 : x
2. Step 2: Convert to fraction form
   2,641.65/3,980.61 = 2,189.57/x
3. Step 3: Cross multiply
   2,641.65x = 3,980.61 × 2,189.57
4. Step 4: Simplify right side
   2,641.65x = 8,715,804.33
5. Step 5: Solve for x
   x = 8,715,804.33/2,641.65
6. Step 6: Final answer
   x = 3,299.38