Constructed 67424

There are six lines 3 cm, 4 cm, 5 cm, 7 cm, 8 cm, and 9 cm long, two of each length. How many isosceles triangles can be constructed from them? List all options.

Correct answer:

n =  20

Step-by-step explanation:

$$\begin{gathered} a+b>c \\ b+c>a \\ a+c>b \\ 3,3,4 \\ 3,3,5 \\ 4,4,3 \\ 4,4,5 \\ 4,4,7 \\ 5,5,3 \\ 5,5,4 \\ 5,5,7 \\ 5,5,8 \\ 5,5,9 \\ 7,7,3 \\ 7,7,4 \\ 7,7,5 \\ 7,7,8 \\ 7,7,9 \\ 9,9,3 \\ 9,9,4 \\ 9,9,5 \\ 9,9,7 \\ 9,9,8 \\ n=20 \end{gathered}$$

Try another example