Question

Which triangle is ​△ABC​ similar to and why?

Answer 1

△ABC is similar to △JKL by ​ AA Similarity Postulate.

Explication:

For ΔABC 

m∠A + m∠B + m∠C = 180°
  20° +   80° + m∠C = 180°
      100° + m∠C = 180°
            m∠C = 80°

Two angle pairs are congurent ⇒ △ABC ~ △JKL