Finding the Fourth Proportional to 2,109.90, 3,165.99 and 878.16

Step by Step Solution

1. Step 1: Write the proportion equation
   2,109.90 : 3,165.99 = 878.16 : x
2. Step 2: Convert to fraction form
   2,109.90/3,165.99 = 878.16/x
3. Step 3: Cross multiply
   2,109.90x = 3,165.99 × 878.16
4. Step 4: Simplify right side
   2,109.90x = 2,780,225.56
5. Step 5: Solve for x
   x = 2,780,225.56/2,109.90
6. Step 6: Final answer
   x = 1,317.71