Finding the Third Proportional to 139.88 and 215.69

Step by Step Solution

1. Step 1: Write the proportion equation
   139.88 : 215.69 = 215.69 : x
2. Step 2: Convert to fraction form
   139.88/215.69 = 215.69/x
3. Step 3: Cross multiply
   139.88x = 215.69 × 215.69
4. Step 4: Simplify right side
   139.88x = 46,521.10
5. Step 5: Solve for x
   x = 46,521.10/139.88
6. Step 6: Final answer
   x = 332.59