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.
Circle C1 can be dilated at its center by a scale factor of 1/2. Then the image can be translated left 4 and down 6. This will map circle C1 onto circle C2 and prove they are similar.
