Finding the Fourth Proportional to 2,172.58, 2,997.78 and 1,288.06

Step by Step Solution

1. Step 1: Write the proportion equation
   2,172.58 : 2,997.78 = 1,288.06 : x
2. Step 2: Convert to fraction form
   2,172.58/2,997.78 = 1,288.06/x
3. Step 3: Cross multiply
   2,172.58x = 2,997.78 × 1,288.06
4. Step 4: Simplify right side
   2,172.58x = 3,861,320.51
5. Step 5: Solve for x
   x = 3,861,320.51/2,172.58
6. Step 6: Final answer
   x = 1,777.30