I don't believe a line can intersect a circle at three points, but they sure can at two. When a line touches a circle at one point it is called a tangent. When a line touches at two points it is called a secant. See the attached diagram (thanks wikipedia). Don't confuse secant with chord. A chord is a line segment, while a secant is a line. So the secant keeps on going while a chord stops at the circumference.
To solve for x in:
Multiply both sides by 4,
Then divide both sides by 3,
For the triangle, we know the perimeter is 52, so