Finding the Third Proportional to 11.31 and 15.91

Step by Step Solution

1. Step 1: Write the proportion equation
   11.31 : 15.91 = 15.91 : x
2. Step 2: Convert to fraction form
   11.31/15.91 = 15.91/x
3. Step 3: Cross multiply
   11.31x = 15.91 × 15.91
4. Step 4: Simplify right side
   11.31x = 253.18
5. Step 5: Solve for x
   x = 253.18/11.31
6. Step 6: Final answer
   x = 22.38