Answer:
51 degrees
Step-by-step explanation:
Complementary angles are two angles whose sum is (90degrees). If one is given an angle measure and needs to find its complementary angle, then all one has to do is subtract the given angle measure from (90degrees).
90 - 39 = 51
 
        
                    
             
        
        
        
Answer:
TRUE
Step-by-step explanation:
We are given 2 triangles, ∆ABC and ∆DEF.
For the two trinagles to be considered similar, both must have their set of corresponding angles congruent to each other. That is, their corresponding angles are equal.
From the information given, the following are the set of corresponding angles:
<B = <E = 31°
<B = <D = 90°
<C = <F = 59° [180 - (90+31)] 
The corresponding angles of both triangles are congruent. Therefore, it is guaranteed that ∆ABC is similar to ∆DEF (∆ABC ~ DEF).