ANSWER
B. 12
EXPLANATION
The given triangle is isosceles, because two of the arms are equal.
The angles directly under these two arms and the base are equal.
Therefore the three angles of the isosceles triangle are
84°, 4x°,4x°
The sum of these angles is 180°
[tex]84 + 4x + 4x = 180[/tex]
[tex]84 + 8x = 180[/tex]
Group similar terms,
[tex]8x = 180 - 84[/tex]
[tex]8x = 96[/tex]
Divide both sides by 8
[tex]x = 12[/tex]
The correct choice is B.
