Notes on lesson on Geometry |




An angle is a figure formed by two rays, called the sides of the angle sharing a common end point.The types of angles are classified according to their measure. The angles are; adjacent angles, complementary angles, supplementary angles, vertical angles etc.

Triangle Theorems

Triangles are governed by two important inequalities. The triangle inequality theorem states that any side of a triangle is always shorter than the sum of the other two sides. This note contains information about triangle theorem.

Congurency and Similarities

Two triangles are congruent if they have exactly the same three sides and exactly the same three angles. Similar triangle has the same shape, but the size may be different. Two triangles are similar if and only if the corresponding sides are in proportion and the corresponding angles are congruent.


A quadrilateral is a polygon with four edges (or sides) and four vertices or corners. Sometimes, the term quadrangle is used, by analogy with triangle, and sometimes tetragon for consistency with pentagon (5-sided), hexagon (6-sided) and so on.


The fixed point is called the centre of the circle. The distance from the centre of the circle to any point on the circle is called the radius of the circle.A circle is a simple shape in geometry. It is the set of all points in the plane that are at a given distance from the given point.


The word construction in geometry has a very specific meaning: the drawing of geometric items such as lines and circles using only compasses and straightedge(ruler).In Geometry construction means to draw shapes, angles and lines accurately by using a compass, ruler and a pencil.