Finding the Third Proportional to 90.88 and 139.69

Step by Step Solution

1. Step 1: Write the proportion equation
   90.88 : 139.69 = 139.69 : x
2. Step 2: Convert to fraction form
   90.88/139.69 = 139.69/x
3. Step 3: Cross multiply
   90.88x = 139.69 × 139.69
4. Step 4: Simplify right side
   90.88x = 19,512.60
5. Step 5: Solve for x
   x = 19,512.60/90.88
6. Step 6: Final answer
   x = 214.72