You can split things in half. 
Bisection means splitting something into two equal parts. 
Bisection is a way to split something into two equal parts. These parts are called congruent. This means they have the same shape and size.
One common way is to bisect a line segment. A segment bisector is a line that goes through the middle. We call that middle point the midpoint. A perpendicular bisector is a special kind of line. It meets the segment at a right angle. Every point on this line is the same distance from both ends.
You can also bisect an angle. An angle bisector is a line that splits an angle into two equal parts. In a triangle, the three angle bisectors meet at one point. This point is called the incenter.
In three-dimensional space, we use a flat surface to split things. This is called a bisector plane. It can split a line segment at its midpoint.
Math tools like a compass and straightedge help us find these lines. You can use them to draw perfect circles. This helps you find the exact center of a shape. Bisection helps us find balance in math.
Bisection is a way to divide something into two equal parts. In geometry, these two parts are called congruent. This means they have the same size and the same shape.
There are different ways to work with these lines. A segment bisector passes through the exact middle of a line. We call this middle point the midpoint. A perpendicular bisector is even more special. It meets the segment at a right angle. Every point on a perpendicular bisector is the same distance from both ends of the segment.
In classical geometry, people used simple tools to find these lines. They used a straightedge and a compass. You can bisect a segment by drawing circles with a compass. You place the compass on the endpoints of the segment. You draw arcs of equal size that cross each other. The line through those crossing points is the perpendicular bisector. 
Many interesting things happen when these lines meet. In a triangle, the three angle bisectors all meet at one single point. This special point is called the incenter.
Bisection helps us find the center of many shapes. For example, the three perpendicular bisectors of a triangle meet at the circumcenter. This is the center of a circle that touches all three corners. In a triangle, the medians also bisect the sides. The medians meet at a point called the centroid. This point is the center of mass for the triangle.
In geometry, bisection is the process of dividing a geometric figure into two equal or congruent parts. When two parts are congruent, they possess the exact same shape and size. This division is typically achieved using a bisector, which is a line, ray, or plane that performs the split.
There are several distinct types of bisectors depending on what is being divided. A segment bisector is a line that passes through the midpoint of a given line segment. The most specific version is the perpendicular bisector. This line meets the segment at its midpoint at a right angle, or 90 degrees. An important property of a perpendicular bisector is that every point on it is equidistant from the segment's two endpoints.
Angle bisection involves dividing an angle into two smaller angles of equal measure. An angle has only one unique bisector. Every point located on an angle bisector is equidistant from the two sides, or legs, of the angle. There are two ways to view this: the interior bisector divides an angle smaller than 180 degrees into two equal parts. The exterior bisector divides the supplementary angle, which is the angle formed by one side and the extension of the other. The interior and exterior bisectors of an angle are always perpendicular to each other.
In classical geometry, these lines are often found using only a straightedge and a compass. To construct a perpendicular bisector, you draw two intersecting circles of equal radius. The centers of these circles are the endpoints of the segment. The line passing through the two points where the circles intersect is the perpendicular bisector. 
Bisection reveals remarkable patterns within triangles. The three interior angle bisectors of any triangle are concurrent, meaning they all meet at a single point called the incenter.
Other types of lines in a triangle also rely on bisection. A median is a line segment that connects a vertex to the midpoint of the opposite side. Because it hits the midpoint, the median bisects that side. The three medians of a triangle meet at a point called the centroid. The centroid is the center of mass for a triangle with uniform density. Additionally, the three perpendicular bisectors of a triangle's sides meet at the circumcenter. This is the center of the circle that passes through all three vertices of the triangle.
Bisection is also used to study more complex polygons and curves. In a rhombus, each diagonal bisects the opposite angles. For a convex quadrilateral, the internal angle bisectors might form a cyclic quadrilateral, or they might all meet at a single point. If they meet at one point, the shape is called a tangential quadrilateral. Even in advanced curves like a parabola, bisection appears. A tangent to a parabola at any given point bisects the angle between the line to the focus and the perpendicular line to the directrix.
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