Finding the Fourth Proportional to 1,139.50, 1,709.25 and 455.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.50 : 1,709.25 = 455.98 : x
2. Step 2: Convert to fraction form
   1,139.50/1,709.25 = 455.98/x
3. Step 3: Cross multiply
   1,139.50x = 1,709.25 × 455.98
4. Step 4: Simplify right side
   1,139.50x = 779,383.82
5. Step 5: Solve for x
   x = 779,383.82/1,139.50
6. Step 6: Final answer
   x = 683.97