Area of a triangle = base x height / 2
64 = base x height / 2
(multiply 2 on both sides)
128 = base x height
then if base= 16 and height = 8 then 16 x 8 = 128
thus the base is 16 which is twice the height:8
Step-by-step explanation:

sin 45 = opp/hyp
sin 45 = 4 / y
y = 4/sin 45
y = 4 /((sqrt2)/2)=4* sqrt(2)
tan 45 =opp/adj
tan 45 = 4/(x-3)
1 = 4/(x-3)
x-3 = 4
x=7
B