Finding the Fourth Proportional to 2,172.02, 2,997.31 and 1,287.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,172.02 : 2,997.31 = 1,287.30 : x
2. Step 2: Convert to fraction form
   2,172.02/2,997.31 = 1,287.30/x
3. Step 3: Cross multiply
   2,172.02x = 2,997.31 × 1,287.30
4. Step 4: Simplify right side
   2,172.02x = 3,858,422.18
5. Step 5: Solve for x
   x = 3,858,422.18/2,172.02
6. Step 6: Final answer
   x = 1,776.42