The value of side a is 30
Similar triangles have congruent angles and proportional side lengths. Corresponding angles are equal, and the ratios of corresponding sides are constant.
This similarity property allows triangles to share proportional dimensions while having different absolute sizes.
Triangle XYZ is simar to triangle ABC
13/78 = 5/a
13a = 390
a = 390/13
a = 30
Therefore, the value of side a is 30