(1) Ans. The points that lie on a line are called collinear point.

(2) Ans. A figure that have a three sides are called triangle.

(3) A triangle whose all sides are different measure are called scalene triangle.

(4) Ans. A triangle whose two sides are equal are called Isosceles triangle.

(5) Ans. A triangle whose all sides are equal are called equilateral triangle.

(6) Ans. A triangle whose one angle measure 90 degree is called right triangle.

(7) Ans. A triangle whose one angle measure more than 90 degree is called obtuse triangle.

(8) Ans. A triangle whose all side measure less than 90 degree is called acute angled triangle.