Finding the Fourth Proportional to 2,172.88, 3,259.28 and 874.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,172.88 : 3,259.28 = 874.31 : x
2. Step 2: Convert to fraction form
   2,172.88/3,259.28 = 874.31/x
3. Step 3: Cross multiply
   2,172.88x = 3,259.28 × 874.31
4. Step 4: Simplify right side
   2,172.88x = 2,849,631.43
5. Step 5: Solve for x
   x = 2,849,631.43/2,172.88
6. Step 6: Final answer
   x = 1,311.46