9514 1404 393
Answer:
(b) 40°
Step-by-step explanation:
Angle x and the one marked 70° are alternate interior angles, so are congruent. The sum of the two base angles of the isosceles triangle is ...
x° +x° = 70° +70° = 140°
So, the remaining angle 1 in the triangle is ...
180° -140° = 40°
∠1 = 40°
