3) What is the shape of surface if a right circular cone is cut by a plane making the same angle with the axis is parallel to the slant line?

4) What is the shape of surface if a right circular cone is cut by a plane making a smaller angle with the axis, (i.e the plane is not parallel to the slant lined passes through the base)?

5) Which is a practical application of involutes curve?

6) What name the curve traced out by a point on the circumference of a circle that rolls outside another circle of larger diameter?

7) What is set of points on the major axis at equidistant from centre to create the curve of ellipse?