M = (y2-y1)/(x2 -x1)
m = (7 -2)/(5 - 1)
m = 5/4
answer: slope m = 5/4
The correct answer should be c) 3.
To find AB(x) and BC(y), you can do(there are multiple ways you can do this):
tan A = 
tan 60° =
or (tan 60°) · 7 = y
tan 60° = 
√3 · 7 = y
7√3 cm = y
sin B = 
sin 30° =
or 
sin 30° =
= 
x = 
x = 14 cm
AB = 14cm
BC = 7√3 cm
let the line between 2 tria be y
sin 60/8√2 = sin 90/y
y=13.06
sin 45/13.06 = sin 90/x
x=18.46