Answer:
C XD
Step-by-step explanation:
The altitude of a triangle goes from the vertex (corner) to the opposite side. It must be perpendicular to the opposite side ( at a right angle)
XD is an altitude
The number of intersections is the number of solutions
we can see they are paralell so they will never intersect
0
C is the answer
2x+38=180
2x=142 (or x+x=142 from which 2x=142)
x=71
The unknown angles are each 71
You know this answer is logical as, since two sides are 21 it hints that we are looking at an equilateral triangle, which means two of its angles will be the same