Question

in ABC , m B =140 and m C=10. In DEF , m D=30 and m F=10. Which statement about the triangles is true?

Answer 1

In triangle ABC, <B = 140, <C = 10
so <A = 180 - 140 - 10 = 30

In triangle DEF , <D = 30 and <F = 10
so <E = 180 - 30 - 10 = 140

Now you have
<A = <D = 30
<B = <E = 140
<C = <F = 10

Conclusion: triangle ABC is similar to triangle DEF

Answer is the last one.