Which pairs of triangles MUST be similar? a. Triangles 1 and 2 each have one angle in common.
b. Triangles 3 and 4 are both isosceles. They each have a 60 degrees angle.
c. Triangles 5 has a 20 degrees angle and a 100 degrees angle. Triangle has a 20 degrees angle and a 60 degrees angle.
d. Triangle 7 has a 70 degrees angle and a 25 degrees angle. Triangle 8 has a 50 degrees angle and a 105 degrees angle.

B. 3&4 are isosceles.

Step-by-step explanation:

Not 100% sure, just kind of makes sense

Answer is b

Step-by-step explanation:

The triangles are equal considering the congruency ASA

PLS MARK BRAINLIEST I REALLY NEED IT

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12