Answer:
<BAC = 36degrees
Step-by-step explanation:
Find the diagram attached
The sum of the interior angle is equal to the exterior. Hence;
<B + <C = <DAB
6x+40 + x+20 = 180 - 3x
7x+60 = 180 - 3x
7x+3x = 180 - 60
10x = 120
x = 120/10
x = 12
Get <BAC
<BAC = 180 - (180-3x)
<BAC = 180-180+3x
<BAC = 3x
<BAC = 3(12)
<BAC = 36degrees
