I will complete the information missing with information from an equal problem. It might match or not your problem, but undobutedly this will teach you hoiw to solve this problem, which is the idea of my help.
Triangle ABC and triangle DEF are similar. The lengths of AB and AC are 5 units each, and the length of BC is 6 units. If the length of EF is 3 units, then the length of DE is ?. If the measure of the angle ABC is 53°, then measure of the angle DEF is ?
This problem is solved from knowing the properties of similar triangles.
1) In similar triangles the ratio of two corresponding sides is a constant.
So that implies length AB / length DE = length BC / length BC / length EF = length AC / length DF
=> 5 / DE = 6 / 3
=> 5 / DE = 2
=> DE = 5/2 = 2.5
Note tha the length of side DF is also 5/2.
2) In similar triangles the measures of corresponding angles are equals, so measure of angle ABC equals measure of angle EBF
=> meausre of angle EBF = measure of angle ABC = 53°.
