Given that the triangles are corresponding triangles, then ∠B ≅ ∠E, therefore:
m∠B = m∠E
Replacing with data:
3v + 4 = 8v - 6
3v is adding on the left, then it will subtract on the right
6 is subtracting on the right, then it will add on the left
4 + 6 = 8v - 3v
10 = 5v
5 is multiplying on the right, then it will divide on the left
10/5 = v
2 = v
Then, the measure of B is:
m∠B = 3v + 4 = 3(2) + 4 = 10°
The measure of angle B is 10°
