Here we will recall about the basic geometrical concepts.
Basic Geometrical Concepts:
Axiom: It is a proposition that is not proved but considered to be self-evident or subject to necessary decision. Its truth is taken for granted and serves as a starting point for deducing and concluding other truths.
• Whole is greater than the part.
• Things that are equal to same thing are equal to one another.
Statement: It is a question that is definitely true or definitely false.
• Every triangle has three sides. This statement is true.
• No prime number is even. This statement is false.
Theorem: A formula that is provable without any further assumption is called a theorem. A theorem can be deduced from previously accepted statements such as axiom.
• In a right angled triangle, the sum of the squares of two sides is equal to the square of the longest side.
Corollary: Result that is trivial or self-evident from a theorem is known as a corollary. Corollary is simply something which we can prove from some other theorem.
Theorem: The sum of interior angles of a triangle is 180°.
Its corollary: The sum of interior angles of a quadrilateral is 360°.
● Lines and Angles