Finding the Third Proportional to 90.75 and 128.88

Step by Step Solution

1. Step 1: Write the proportion equation
   90.75 : 128.88 = 128.88 : x
2. Step 2: Convert to fraction form
   90.75/128.88 = 128.88/x
3. Step 3: Cross multiply
   90.75x = 128.88 × 128.88
4. Step 4: Simplify right side
   90.75x = 16,608.77
5. Step 5: Solve for x
   x = 16,608.77/90.75
6. Step 6: Final answer
   x = 183.02