Respuesta :

You got it right
<CDA = <ABC = 40
so

<CAD = 180 - 57 - 40
<CAD = 83

Well In This One, Both Of The Triangles Are The Same, So That Means Its Just Double The Angles. And A Triangle Adds Up To 180 Degrees.

So, For Example 
40+57+83=180

So You Just Have To Make Sure It Adds Up To 180 For A Triangle