1)
c^2 < a^2 + b^2 = acute
c^2 > a^2 + b^2 = obtuse
c^2 = a^2 + b^2 = right
so
c^2 = 47^2 = 2209
a^2 + b^2 = 20^2 + 34^2 = 400 + 1156 = 1556
2209 >1156
c^2 > a^2 + b^2 = obtuse
answer is B. obtuse
2)
<A = 90, <B = <C = 45
AC = AB = 12
12^2 + 12^2 = 2 (12^2)
BC = 12√2
answer is C. 12√2 ft
3)
a square cut into 2 equal triangles (2 isosceles triangles)
So it's 45 45 90 right triangle
if hypo = 34 then side = 17√2
answer is C. 17√2 inches