How can I solve this?

We see that the big triangle is an equilateral triangle, so all its angles will measure 60°. Therefore x° will be 60° - 30° = 30°, as he's the base angle of an isosceles triangle having the other base angle of 30°. y will simply be 180° - 60° (remembering that the sum of the angles in a triangle is always 180°).

x = 30

y = 120 degrees.

Step-by-step explanation:

Each angle in the larger equilateral triangle = 60 degrees.

The smaller triangle is isosceles so the 2 base angles are congruent.

So x = 60 - 30 = 30 degrees.

y = 180 - 2(30)

= 120 degrees.

c.

step-by-step explanation: