Answer: X = 10
OK, so the triangle that has 110 and 40 already in it, 110+40=150
all the angles in the triangle have to equal 180
so 180-150 = 30 so that angle that is missing is 30
Next, you look at the triangle beside that one and see that it has two marks on two of the lines, meaning they are equal to each other.
so the angle with 40 on the other triangle, the angle touching that angle is going to be 40 also. The two bottom angles have to be the same because it is an isosceles triangle. so 180-40= 140 divided by 2 = 70
So, the overall big triangle is angle E = 70, angle A is 30+70 = 100
so 180 - 100 - 70 = 10
So X = 10