Finding the Fourth Proportional to 1,139.42, 1,707.42 and 445.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.42 : 1,707.42 = 445.38 : x
2. Step 2: Convert to fraction form
   1,139.42/1,707.42 = 445.38/x
3. Step 3: Cross multiply
   1,139.42x = 1,707.42 × 445.38
4. Step 4: Simplify right side
   1,139.42x = 760,450.72
5. Step 5: Solve for x
   x = 760,450.72/1,139.42
6. Step 6: Final answer
   x = 667.40