We use ASA (angle side angle) to show the two triangles are congruent. Why ASA instead of AAS? Because the single pair of sides are between the two angles.
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Problem 18)
Similar to problem 16, we'll have two pairs of congruent angles, and a pair of congruent sides. However, the sides are NOT between the two angles. So that means we use AAS in this case.
You should purchase 322 boxes. If you take 7.714 decided by 24 solar panels per box, you get 321.416667 and because you can purchase .416667 of a box, you round up to 322