Finding the Third Proportional to 139.22 and 216.42

Step by Step Solution

1. Step 1: Write the proportion equation
   139.22 : 216.42 = 216.42 : x
2. Step 2: Convert to fraction form
   139.22/216.42 = 216.42/x
3. Step 3: Cross multiply
   139.22x = 216.42 × 216.42
4. Step 4: Simplify right side
   139.22x = 46,838.43
5. Step 5: Solve for x
   x = 46,838.43/139.22
6. Step 6: Final answer
   x = 336.44