The sum of all angles of a triangle is always equal to 180°. Therefore, looking at triangle A we have 3 angles, 53°, 68°, and x. The sum of them will be 180:
a)
[tex]x+53+68=180[/tex]Now we solve it for x
[tex]\begin{gathered} x=180-53-68 \\ \\ x=59\degree \end{gathered}[/tex]b)
Same thing here, the angles are 46°, 71°, and x, the sum is equal to 180°:
[tex]\begin{gathered} x+46+71=180 \\ \\ x=180-46-71 \\ \\ x=63\degree \end{gathered}[/tex]c)
Now for C, we have the angles x, x again, and 24°, therefore the sum will be
[tex]\begin{gathered} x+x+24=180 \\ \\ 2x+24=180 \\ \\ 2x=180-24 \\ \\ 2x=156 \\ \\ x=\frac{156}{2} \\ \\ x=78\degree \end{gathered}[/tex]Final answers:
a) x = 59°
b) x = 63°
c) x = 78°