Finding the Third Proportional to 138.59 and 215.47

Step by Step Solution

1. Step 1: Write the proportion equation
   138.59 : 215.47 = 215.47 : x
2. Step 2: Convert to fraction form
   138.59/215.47 = 215.47/x
3. Step 3: Cross multiply
   138.59x = 215.47 × 215.47
4. Step 4: Simplify right side
   138.59x = 46,428.47
5. Step 5: Solve for x
   x = 46,428.47/138.59
6. Step 6: Final answer
   x = 335.02