INTRODUCTION A triangle, you have seen, is a simple closed curve made of three line segments. It has three vertices, three sides and three angles. Here is ∆ABC (Fig 6.1). It has Sides: \(
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MEDIANS OF A TRIANGLE Given a line segment, you know how to find its perpendicular bisector by paper folding. Cut out a triangle ABC from a piece of paper (Fig 6.3). Consider any one of its s
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ALTITUDES OF A TRIANGLE Make a triangular shaped cardboard ABC. Place it upright on a table. How ‘tall’ is the triangle? The height is the distance from vertex A (in the Fig 6.4)
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EXTERIOR ANGLE OF A TRIANGLE AND ITS PROPERTY DO THIS 1.Draw a triangle ABC and produce one of its sides, say BC as shown in Fig 6.7. Observe the angle ACD formed at the point C. This angle lies
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ANGLE SUM PROPERTY OF A TRIANGLE There is a remarkable property connecting the three angles of a triangle. You are going to see this through the following four activities. 1. Draw a triangle.
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TWO SPECIAL TRIANGLES : EQUILATERAL AND ISOSCELES A triangle in which all the three sides are of equal lengths is called an equilateral triangle. Take two copies of an equilateral triangle AB
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SUM OF THE LENGTHS OF TWO SIDES OF A TRIANGLE 1. Mark three non-collinear spots A, B and C in your playground. Using lime powder mark the paths AB, BC and AC. Ask your friend to start from A an
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RIGHT-ANGLED TRIANGLES AND PYTHAGORAS PROPERTY Pythagoras, a Greek philosopher of sixth century B.C. is said to have found a very important and useful property of right-angled triangles given in t
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