Finding the Fourth Proportional to 2,109.65, 3,165.61 and 877.91

Step by Step Solution

1. Step 1: Write the proportion equation
   2,109.65 : 3,165.61 = 877.91 : x
2. Step 2: Convert to fraction form
   2,109.65/3,165.61 = 877.91/x
3. Step 3: Cross multiply
   2,109.65x = 3,165.61 × 877.91
4. Step 4: Simplify right side
   2,109.65x = 2,779,120.68
5. Step 5: Solve for x
   x = 2,779,120.68/2,109.65
6. Step 6: Final answer
   x = 1,317.34