Question

Please help me I don´t get it?

Answer 1

∠1 = 137

∠2 = 43

∠3 = 137

Explanation:

∠2 and 43 are alternate interior angles.

Alternate interior angles are equal.

So,

∠2 = 43.

∠1 and ∠3 are also alternate interior angles,

So,

∠1 = ∠3

∠1 and 42 are linear pair angles.

Sum of linear pair angles is 180,

∠1 + 42 = 180

∠1 = 180 - 43

∠1 = 137

Since,

∠1 = ∠3

So,

∠3 = 137

Hence,

∠1 = 137

∠2 = 43

∠3 = 137

Note : -

Alternate interior angles and linear pair angles are properties of angles.

And are applicable when two lines intersect or more than two lines interest.

Answer 2

A straight line has 180 degrees. To find angle 1, subtract 43 from 180 which is 137.
Angle 2 is also 43 degrees and angle 3 would be 137 degrees.