
via the angle sum formula of sin


which proves the second choice
the third choice is wrong since for x=0,y=0 it will show that 2=1 which is incorrect
for the fourth one you can do some thing similar to choice one just expand the sum formula of sin and that should be true too
so
the first , the second and the fourth are all true
Answer:
corollary,postulate,theorem,definition
A is 5,6 that is the answer for A gotta go but maybe someone else can help with the other ones
Answer:
consecutive = x+x+2
x+x+2 = 4x-20
2x+2=4x-20
2=2x-20
22=2x
x=11
Numbers are 11,13.
Hope this helps plz hit the crown :D
Answer: isosceles
Step-by-step explanation:
By the alternate interior angles theorem, 
Since angles in a triangle add to 180 degrees, 
Since sides opposite equal angles in a triangle are equal,
.
So, triangle ABC is <u>isosceles</u>