Answer:
[tex]\boxed{\bf \angle A=84^o}[/tex]
Step-by-step explanation:
From the given diagram, we can see that ∠B & ∠C are corresponding angles, which means that they are equal. The two angles that form a straight line are supplementary angles (the sum of two supplementary angles is 180°).
[tex]\bf 5x+34^o+\angle C=180^o[/tex]
[tex]\bf 5x+34^o+\angle B=180^o[/tex]
[tex]\bf 5x+34^o+2x+76^o=180^o[/tex]
Now, let's solve for x :-
[tex]\bf (5x+34^o)+(2x+76^o)=180^o[/tex]
[tex]\bf (5x+2x)+(34+76)=180^o[/tex]
[tex]\bf 7x+110=180^o[/tex]
[tex]\bf (7x+110)-110^o=180-110^o[/tex]
[tex]\bf 7x=70^o[/tex]
[tex]\bf \cfrac{7x}{7} =\cfrac{70}{7}[/tex]
[tex]\boxed{\bf x=10^o}[/tex]
Now, in order to find ∠A will substitute the value of x into the expression:-[tex]\bf \angle A=5x+34^o[/tex]
[tex]\bf \angle A=5(10)+34^o[/tex]
[tex]\bf \angle A=84^o[/tex]
______________________