Finding the Third Proportional to 91.13 and 121.31

Step by Step Solution

1. Step 1: Write the proportion equation
   91.13 : 121.31 = 121.31 : x
2. Step 2: Convert to fraction form
   91.13/121.31 = 121.31/x
3. Step 3: Cross multiply
   91.13x = 121.31 × 121.31
4. Step 4: Simplify right side
   91.13x = 14,716.72
5. Step 5: Solve for x
   x = 14,716.72/91.13
6. Step 6: Final answer
   x = 161.50