Answer:
<BAC = 70°
Explanation:
from the picture it's an isosceles triangle,
In an isosceles triangle, if two sides are equal, then the angles opposite to the two sides correspond to each other and are also always equal.
the sum of the interior angles is 180°
so
40 + x + x = 180°
2x = 180 - 40
2x = 140
x = 140 : 2
x = 70
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check
70 + 70 + 40 = 180°
the answer is good