Please help, my score is 89 I have to get to 90 this question is important!

40.4

Step-by-step explanation:

Triangle TUV is similar to triangle XYZ.

Notice the order in which TUV and XYZ are written.

Angles are corresponding to angles in the same position in the names.

<T corresponds to <X.

<U corresponds to <Y.

<V corresponds to <Z.

In similar triangles, corresponding angles are congruent.

<T is congruent to <X.

<U is congruent to <Y.

<V is congruent to <Z.

m<T = m<X = 63.1°

m<U = m<Y

m<V = m<Z = 76.5°

m<X + m<Y + m<Z = 180°

63.1° + m<Y + 76.5° = 180°

m<Y + 139.6° = 180°

m<Y = 40.4°

it is a. 4.2 because 7.6-3.4 gets the remaining length of 4.2. i might be wrong but i am pretty sure this is the answer.