Step-by-step explanation:
Let the angle near point A be
.
Let the angle near point B be
.
Let the angle near point C be
.
Let the external angle near point A be
.
Let the external angle near point B be
.
Let the external angle near point C be
.
According to exterior angle property,exterior angle of an angle is the sum of other two angles.
So,

According to angle sum property,the sum of angles in the triangle add to 

20 buttons in total
Because he has
5 white buttons
2 fewer brown
5-2 =3
So 3 brown
9 more gray than brown
3+9 = 12
12 gray buttons
5+3+12=20
The slope is 4/3.
rise/run
rise = 4
run = 3
Answer:
D) 414
Step-by-step explanation:
Please refer to the attached image for explanations