Finding the Fourth Proportional to 1,238.98, 1,709.81 and 679.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,238.98 : 1,709.81 = 679.50 : x
2. Step 2: Convert to fraction form
   1,238.98/1,709.81 = 679.50/x
3. Step 3: Cross multiply
   1,238.98x = 1,709.81 × 679.50
4. Step 4: Simplify right side
   1,238.98x = 1,161,815.90
5. Step 5: Solve for x
   x = 1,161,815.90/1,238.98
6. Step 6: Final answer
   x = 937.72