Finding the Third Proportional to 90.28 and 139.22

Step by Step Solution

1. Step 1: Write the proportion equation
   90.28 : 139.22 = 139.22 : x
2. Step 2: Convert to fraction form
   90.28/139.22 = 139.22/x
3. Step 3: Cross multiply
   90.28x = 139.22 × 139.22
4. Step 4: Simplify right side
   90.28x = 19,381.86
5. Step 5: Solve for x
   x = 19,381.86/90.28
6. Step 6: Final answer
   x = 214.68