Answer:When two lines intersect they form two pairs of opposite angles, A + C and B + D. Another word for opposite angles are vertical angles. Vertical angles are always congruent, which means that they are equal. Adjacent angles are angles that come out of the same vertex.
It is 1/4 of the area of the larger triangle...basically if you connect the three midpoints of the triangle's sides it creates four identical smaller triangles...
The perimeter is one half of the larger triangle...
