Which line is a line of symmetry of δabc?

a) line b
b) line a
c) line c
d) line d

A)line a

Step-by-step explanation:

Line of symmetry:It is defined the line which is passing through the center of an figure and divides the figure into two equal halves.

In other words we can say that

Line of symmetry: When a figure reflect over a line  and the figure remains same .Then , the figure has reflection of symmetry or line  symmetry.The line that reflects over is called line of symmetry.

The line of symmetry divides the figure into two mirror image halves.

From given figure, we can see that

line a is passing through the center of the triangle ABC and divides the triangle ABC into two equal halves.

But , line b ,line c and line d  do not  divide  the triangle ABC into two equal halves .Hence, these lines are not line of symmetry of triangle ABC.

Hence, the line of symmetry of triangle ABC is line a.

i belive those are the ones that are under 90 degreese.