Finding the Third Proportional to 91.31 and 128.25

Step by Step Solution

1. Step 1: Write the proportion equation
   91.31 : 128.25 = 128.25 : x
2. Step 2: Convert to fraction form
   91.31/128.25 = 128.25/x
3. Step 3: Cross multiply
   91.31x = 128.25 × 128.25
4. Step 4: Simplify right side
   91.31x = 16,448.06
5. Step 5: Solve for x
   x = 16,448.06/91.31
6. Step 6: Final answer
   x = 180.13