Question

what is the value of the missing angle (?) *

Explanation:

Step1: Teorema de ángulos adyacentes

$$130^{\circ}+\alpha = 180^{\circ}$$
$$\alpha = 180^{\circ}-130^{\circ}=50^{\circ}$$

Step2: Suma de ángulos internos de un triángulo

$$\alpha + 20^{\circ}+? = 180^{\circ}$$
$$50^{\circ}+20^{\circ}+? = 180^{\circ}$$
$$? = 180^{\circ}-50^{\circ}-20^{\circ}$$

Answer:

$$110^{\circ}$$