Remember the SAS rule is that you know the measure of 2 sides and their angle in between. (Note that SSA side side angle DOESN'T work.) For the first question we know that sides JH and LM are congruent, and sides GJ and MK are as well. Secondly, we know that angles M and J are congruent. The question is; does this problem follow the SAS (side angle side) rule? Yes, their are two proven congruent sides on the two triangles, and the angle between them is proven congruent as well.
Second one is congruent because it follows the SSS rule (side side side) ie: all sides are congruent, so therefore the triangles are congruent.
Think about the third one. Is it congruent or not. (To be congruent it has to follow SSS, or SAS) Comment below so I can correct you.
First you need to divide 125 / 25 which is 5 then you do subtraction 21 x 5 which is 105, then you subtract again 125 - 105 which is 20, 20 light bulbs will be broken. Or you could have just multiplied 5 by 4 which is the amount of light bulbs that were broken which is a lot easier...