Lines k and l are parallel. When lines k and l are cut by the transversals below, an isosceles triangle is formed.

The angle x and 70 are alternate interior so that means they measure the same.

In an isoceles triangle the base angles are the same so that means that both the x angles are 70.

Now we can subtract their sum by 180 to find the measure of angle 1.

180 - (70 + 70) = 40

So the measure of angle 1 is 40.

Hope this helps :)