Answer:
D, 60°
Explanation:
These lines on all angles of the triangle mean all of the angles are equal to each other!
Remember, ALL triangles equal 180°
There are 3 angles that share 180° degrees!
Let's divide 180° by 3 to see what EACH ANGLE equals
180 ÷ 3 = 60
All of these angles are equal to 60°
Or, in other words, angle 1 = 60°