Finding the Third Proportional to 69.50 and 138.50

Step by Step Solution

1. Step 1: Write the proportion equation
   69.50 : 138.50 = 138.50 : x
2. Step 2: Convert to fraction form
   69.50/138.50 = 138.50/x
3. Step 3: Cross multiply
   69.50x = 138.50 × 138.50
4. Step 4: Simplify right side
   69.50x = 19,182.25
5. Step 5: Solve for x
   x = 19,182.25/69.50
6. Step 6: Final answer
   x = 276.00