12. Find the values of x and y.
AB = AC .....so .....angles ABD = ACD
So....we have that
47 + 47 + 2y = 180
94 + 2y = 180 subtract 94 from both sides
2y = 86 divide both sides by 2
y = 43°
And
47 + x + y = 180
47 + x + 43 = 180
90 + x = 180 subtract 90 from both sides
x = 90°
