Finding the Third Proportional to 119.50 and 258.50

Step by Step Solution

1. Step 1: Write the proportion equation
   119.50 : 258.50 = 258.50 : x
2. Step 2: Convert to fraction form
   119.50/258.50 = 258.50/x
3. Step 3: Cross multiply
   119.50x = 258.50 × 258.50
4. Step 4: Simplify right side
   119.50x = 66,822.25
5. Step 5: Solve for x
   x = 66,822.25/119.50
6. Step 6: Final answer
   x = 559.18