Problem 1
Answers:
a = 6
b =

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Reason:
The short leg is opposite the smallest angle. For any 30-60-90 triangle, the short leg is half the hypotenuse. This means the short leg is 12/2 = 6 units long. That's why a = 6.
The long leg is
times longer compared to the short leg.

This template applies to 30-60-90 triangles only.
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Problem 2
Answer:
a = 7
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Reason:
We use the same idea mentioned in problem 1. The short leg is half as long as the hypotenuse. It works for 30-60-90 triangles only.