Find the value of x.

#9,10,11,&12

Step-by-step explanation:

9). It's given in the triangle → Two angles are equal in measure

   Therefore, by the definition of an isosceles triangle, opposite sides of the equal angles are equal in measure.

   x = 12

10). Two sides of the given triangles are equal in length.

    By the definition of an isosceles triangle, opposite angles of the equal sides of the triangle will be equal in measure.

    Therefore, y = 55°

    By the triangle sum theorem,

    x° + y° + 55° = 180°

    x° + 55° + 55° = 180°

    x = 180 - 110

    x = 70°

11). By the definition of an isosceles triangle, opposite sides of the equal angles will be equal in measure.

    x + 3 = 12

    x = 9

12). By the definition of an isosceles triangle, opposite angles of the equal sides of the triangle will be equal in measure.

    m∠2 = 53°

    x + 65 = 53

    x = 53 - 65

    x = -12

21

jk it's 20

step-by-step explanation: