isocoleese means 2 angles are same, normally the base angles
so since it says they measure 42
rememeber that all angles in traingle add to 180
so base angles+vertex angle=180
base angles aer both 42 so
2 times 42+vertex angle=180
42 times 2=84
so
if veretx angle=z then
84+z=180
answer is B
