A) side-side-side triangle similarity postulate
b) angle-angle triangle similarity postulate
c) angle-side-angle triangle similarity postulate
d) hypotenuse-lag triangle similarity postulate

The question tells you that  the 3 corresponding angles are equal.

For similarity you only have to know that 2 corresponding angles are equal.

The answer is B.) Angle-Angle Triangle Similarity Postulate, however the extra pair of congruent angles were unnecessary since the Angle-Angle Similarity Postulate only needs two pairs of angles to be congruent in order to be true.

Step 1: 6x-10=1; step 2: 6x=11