What is the best estimate for the value of the expression?

1. are the triangles similar and if so why? what is the value of x? show your work.

Is the square root of 4 plus the square root of 16 rational?

Which must be true in order for the relationship △zyv ~ △xwv to be correct? zy ∥ wx ∠z ≅ ∠y and ∠w ≅ ∠x zv ≅ vy and wv ≅ vx ∠z ≅ ∠x and ∠w ≅ ∠y