What is the value of a° in the figure shown below?
Select one:
A. 15o
B. 18o
C. 22o
D. 30o
E. 45o

Answer:
B) a = 18°
Step-by-step explanation:
Sum of all angles of the triangle = 180°
a + 3a + 6a = 180
10a = 180
a = 180/10
a = 18°