Step-by-step explanation:
the picture is not representing the real angle sizes. so, don't let yourself get confused by that.
the right neighbor angle of 90° at E is also 90°.
it has to be, because it is the supplementary angle to the left 90° (that means together they are 180°).
remember, all angles around a single point on one side of a line have to sum up to 180° (because the line can be seen as the diameter of a circle, with the point being the center of the circle, and so one side of the line is representing a half-circle and therefore 180°).
for the same reason angle 1 (the lower neighbor of the 90° angle at A) is also 90°.
for the same reason the lower neighbor angle of the 60° angle at E is 180 - 60 = 120°.
for the same reason the angle ABC is 180 - 40 = 140°.
for the angle BCD we need to remember :
the sum of interior angles of a polygon with n sides is
(n − 2) × 180°.
in our case ABCDE has 5 sides, so the sum of all interior angles is
(5 - 2) × 180 = 3×180 = 540°
we know 4 of the interior angles already, so
angle BCD = 540 - 90 - 90 - 120 - 140 = 100°
x is now the supplementary angle to the angle BCD.
so,
x = 180 - 100 = 80°
