TRIANGLE A plane figure formed by three non-parallel line segments is called a triangle.

Two non - parallel line segments will always intersect.

In each of the following, state if the statement is true (T) or false (F): A triangle has three sides. A triangle may have four vertices. Any three line-segments make up a triangle. The interior of a triangle includes its vertices. The triangular regain includes the vertices of the corresponding triangle. The vertices of a triangle are three collinear points. An equilateral triangle is isosceles also. Every right triangle is scalene. Each acute triangle is equilateral. No isosceles triangle is obtuse.

Study the given figure and answer the following questions: Name any two line segments inside the triangle ABC.

In each of the following, state if the statement is true (T) or false (F). A triangle has three sides A triangle may have four vertices. Any three line-segment make up a triangle The interior of a triangle includes its vertices. The triangular region includes the vertices of the corresponding triangle. The vertices of a triangle are three collinear points. An equilateral triangle is scalene. Every right triangle is scalene. Each acute triangle is equilateral. No isosceles triangle is obtuse.

Twenty points are marked on a plane so that non three points are collinear except 7 points. How many triangle can be formed by joining the points?