Finding the Fourth Proportional to 1,605.19, 2,216.31 and 1,007.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,605.19 : 2,216.31 = 1,007.89 : x
2. Step 2: Convert to fraction form
   1,605.19/2,216.31 = 1,007.89/x
3. Step 3: Cross multiply
   1,605.19x = 2,216.31 × 1,007.89
4. Step 4: Simplify right side
   1,605.19x = 2,233,796.69
5. Step 5: Solve for x
   x = 2,233,796.69/1,605.19
6. Step 6: Final answer
   x = 1,391.61