If the question refers to a single completely geometrically straight line of finite length in a plane, then a straight line will have two lines of symmetry. One symmetry line is perpendicular to the line being discussed and one symmetry line coincides with the line being discussed. The symmetry operation here is the one where every point of the figure is flipped perpendicularly across the symmetry line and the object is symmetric if that flipping produced exactly the same set of points. (Said differently, if flipping the set of points through a line produced an exact replica of the original set of points, then the like determining the flip is a symmetry line.) One level of complication occurs if the straight line which is the subject of the symmetry question is an infinitely long straight line. In such a case one symmetry line still coincides with the actual line, but all lines that are perpendicular to the straight line will be lines of symmetry. Thus, an infinitely long straight line has no single point as its "middle" and has an infinitely many symmetry lines consisting of all possible lines perpendicular to the original line.
A rectangle is a possible candidate, as is an ellipse.
Yes. Tigers have bilateral symmetry. Bilateral symmetry means something has symmetry across one plane (known as the sagittal plane, and directly down the centre of their body), which means one side of their body approximately mirrors the other side.
Reflectional symmetry
a plane triangle is a normal triangle, like the isosceles, right angled, equilateral and scalene triangle.
there are two plane symmetry on triangular prism.
Lines which lie on the same plane and have the same length are known as symmetry lines
It is a circle whose lines of symmetry are infinite
Rotational symmetry refers to symmetry of the figure when it is rotated about a single point in the same plane. Lines of symmetry apply to reflections. You do not have lines of rotational symmetry.
3D shapes don't have lines of symmetry they have plane's of symmetry.
Icosahedron is a polyhedron having twenty plane faces.
If it is a right circular cone, it has an infinite number of planes of symmetry. If it is an oblique circular cone, it has one plane of symmetry.
A circle
At a very detailed level, none since it has one asymmetrically located heart. Superficially it has one plane of symmetry and so any one of the infinitely many lines in that plane will be a line of symmetry.
It could have just one - a plane (not plan!) parallel to its bases and halfway between them.
An animal with bilateral symmetry is divided by one line into two equal halves. This line is called the sagittal plane.
A basketball has an infinite number of lines of symmetry. This is because a basketball is a perfect sphere, and any plane passing through its center will divide it into two equal halves that are symmetrical. Therefore, there are an infinite number of lines of symmetry that can be drawn on a basketball.