Question

Which pair of triangles can be proven congruent by SAS?

Answer 1

Answer: The first pair of triangles can be proven congruent by SAS.

Step-by-step explanation:

SAS postulate says that if two sides and the included angle of a triangle are equal to two sides and the included angle of another triangle, then the two triangles are said to be congruent.

In the first pair of triangles the included angle of a triangle are equal to two sides and the included angle of another triangle, therefore by SAS postulate the two triangles are said to be congruent.

In the second figure, the pair of triangles are congruent by ASA postulate not SAS.

In the third figure, the pair of triangles are not congruent by any postulate or theorem [Because there is no SSA rule].

In the fourth figure, the pair of triangles are congruent by SSS postulate not SAS.

Answer 2

Hi!
SAS stands for Side Angle Side
So you need two sides and then the angle needs to be between them. 
The first one works because the angle is in-between the 2 sides
The second one doesn't work because there are actually 2 angles and you only need one
The third one doesn't work because the angle isn't between both the sides.
The fourth one doesn't work because there are only sides and no angles. 
So it's only the first one!
Hope this helps!