B. 45. The two angles B and A are both 45 to make 90 and angle C is a 90 degree angle so they come together for 180 degrees total
It is 1/4 of the area of the larger triangle...basically if you connect the three midpoints of the triangle's sides it creates four identical smaller triangles...
The perimeter is one half of the larger triangle...
Let

Integrate by parts, taking
<em>u</em> = <em>x</em> ==> d<em>u</em> = d<em>x</em>
d<em>v</em> = sin<em>ᵐ </em>(<em>x</em>) d<em>x</em> ==> <em>v</em> = ∫ sin<em>ᵐ </em>(<em>x</em>) d<em>x</em>
so that

There is a well-known power reduction formula for this integral. If you want to derive it for yourself, consider the cases where <em>m</em> is even or where <em>m</em> is odd.
If <em>m</em> is even, then <em>m</em> = 2<em>k</em> for some integer <em>k</em>, and we have

Expand the binomial, then use the half-angle identity

as needed. The resulting integral can get messy for large <em>m</em> (or <em>k</em>).
If <em>m</em> is odd, then <em>m</em> = 2<em>k</em> + 1 for some integer <em>k</em>, and so

and then substitute <em>u</em> = cos(<em>x</em>) and d<em>u</em> = -sin(<em>x</em>) d<em>x</em>, so that

Expand the binomial, and so on.
Just separate them into there own boxes, which is 38ft