Finding the Third Proportional to 138.38 and 298.69

Step by Step Solution

1. Step 1: Write the proportion equation
   138.38 : 298.69 = 298.69 : x
2. Step 2: Convert to fraction form
   138.38/298.69 = 298.69/x
3. Step 3: Cross multiply
   138.38x = 298.69 × 298.69
4. Step 4: Simplify right side
   138.38x = 89,214.22
5. Step 5: Solve for x
   x = 89,214.22/138.38
6. Step 6: Final answer
   x = 644.73