Finding the Fourth Proportional to 1,238.98, 1,709.78 and 679.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,238.98 : 1,709.78 = 679.45 : x
2. Step 2: Convert to fraction form
   1,238.98/1,709.78 = 679.45/x
3. Step 3: Cross multiply
   1,238.98x = 1,709.78 × 679.45
4. Step 4: Simplify right side
   1,238.98x = 1,161,710.02
5. Step 5: Solve for x
   x = 1,161,710.02/1,238.98
6. Step 6: Final answer
   x = 937.63