The two "shorter" sides are referring to the legs of the triangles, because the hypotenuse is the largest side. Looking at this, we can find that it's a 3-4-5 triangle, which means that the scaling factor is 3, because 9/3 =3, 12/3=4, meaning we multiply 5 by 3 to get 15.
The answer is B. To find the Circumference (what you're looking for) you use 2×pi×radius. Which is 2×pi×7. In terms of pi that's just 2×7, which equals 14. So that means your answer is 14pi.
