Answer:
x° = 123
Step-by-step explanation:
this triangle is isoceles so it has 2 congruent angles.
let y be the second angle
the sum of a triangle's angle is 180°
[tex]180 = 66 + y + y \\180 = 66 + 2y[/tex]
add [tex]-66[/tex] to both sides
[tex]180 - 66 = 2y + 66 - 66 \\114 = 2y[/tex]
divide both sides by 2
[tex]\frac{114}{2} = \frac{2y}{2}[/tex]
[tex]57 = y[/tex]
we khow that [tex]x + y = 180[/tex]
[tex]x + y = 180 \\x + 57 = 180[/tex]
add -57 to both sides
[tex]x + 57 - 57 = 180 - 57 \\x = 123[/tex]
