Answer:
x = 35 degrees
Step-by-step explanation:
A good think to keep in mind with this one is that the angles of all triangles add up to 180 degrees. Also, any line dissecting a straight line will create two angles that add up to 180 degrees and the opposite angles are similar and equal.
In this case, we can see that the angle above the lower 105 degree angle is a similar angle, meaning it is also 105 degrees. So the larger triangle in the center has angles of 40 degrees, 105 degrees, and x. This means that x + 40 + 105 = 180 degrees.
This leaves us with our final equation:
x = 180 - 105 - 40 = 35 degrees
