Question

The top left angle measure is ?

Answer 1

x = 100°

In a parallelogram all the interior angles must add up to 360°

Opposite angles of a parallelogram are equal

360° = x + x + 80° + 80°

360° = 2x + 160°

2x = 200°

x = 100°

Alternatively:

x and 80° are corresponding angles because they are on the same line that crosses two parallel lines. Corresponding angles are complementary and add up to 180°.

180° = x + 80°

x = 100°

Answer 2

The given figure is of parallelogram,

x+80=180( being co interior angle )

x=180-80

or,x=100