Finding the Fourth Proportional to 2,215.67, 3,320.01 and 1,288.89

Step by Step Solution

1. Step 1: Write the proportion equation
   2,215.67 : 3,320.01 = 1,288.89 : x
2. Step 2: Convert to fraction form
   2,215.67/3,320.01 = 1,288.89/x
3. Step 3: Cross multiply
   2,215.67x = 3,320.01 × 1,288.89
4. Step 4: Simplify right side
   2,215.67x = 4,279,127.69
5. Step 5: Solve for x
   x = 4,279,127.69/2,215.67
6. Step 6: Final answer
   x = 1,931.31