Answer:
18 units.
Explanation:
We have been given a graph of a triangle and we are asked to find the length of side BC.
We can see from our triangle that measure of angle B is equal to measure of angle C, which means that our given triangle is an isosceles triangle.
Now we will find the value of x by equating the side corresponding to angle B and C to each other as:





Let us divide both sides of our equation by 3.


To find the length of side BC we will substitute
in the expression given for side BC.




Therefore, the length of side BC is 18 units.