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:TRIANGLE AND ITS PARTS; MEDIANS AND ALTITUDES OF TRIANGLE, , Atriangle isa simple closed curve made of three line segments. It has three vertices, three A, j des and three angles. In the adjoining fig., we have AABC. It has sides: AB, BC, CA, , : Vertices: A, B, C, } angles: <BAC, ZABC, ZBCA c, : The side opposite to vertex A is BC. Angle opposite to side AB is ZC. B, ? Classification of Triangles mn, ; @ Classification according to sides, ; {2} Ascalene triangle - no two sides equal in length., , , , ) An isosceles triangle - two sides equal in length., , Q i 5 R, triangle, , {) An equilateral triangle - all three sides equal in length., Note: An equilateral triangle is also isosceles., , Equilateral, : triangle, : +, : (0) Classification according to angles Be,, : (@ Aright triangle or right-angled triangle - one angle is a right angle. Xe,, B Rghang c, triangle, D, (®) An obtuse angled triangle - one angle is obtuse. ee, E F, Obtuse angled, , triangle, , Scanned with CamScanner

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ABC is a triangle in which AB = BC = CA, Hence, AABC is equilateral., , On measuring each angle; 60°, , we find that, , mZA =mZB = mZC = 60°, , Hence, each angle of an A\60° 60°C, equilateral triangle is of, , measure 60°. X, , A triangle in, which two, sides are of ya., , , , , , , , Ete e. a , b+c>a, , atc>b n, Tf any of three relations, , -does not hold then no B, : angle is possible., , , , Scanned with CamScanner