The development of curved surface of a cone is a sector of a circle, radius and length of arc of which are respectively equal to slant height and circumference of base-circle of cone.

If any of solid in two of intersecting solids is having curves surface that is cylinder, cone, sphere etc line of intersection will give curve only but not straight line for getting line of intersection straight line both solids should not have curved surfaces.

The two solids are assumed to be cut by a series of cutting planes. The cutting planes may be vertical, edgewise or oblique. The cutting planes are so selected as to cut surface of one of solids in straight lines and that of or in straight lines or circle.

Approximation method is used to develop objects of double curved or warped surfaces as sphere, paraboloid, ellipsoid, hyperboloid and helicoid. Triangulation method is used for transition pieces. This is simply a method of dividing a surface into number of triangles and transferring m into development.

A zone is portion of sphere enclosed between two planes perpendicular to axis. A lune is portion between two planes which contain axis of sphere. A sphere is approximately developed by se two methods.

Parallel-line method is employed in case of prisms and cylinders in which stretch out-line principle is used. Radial-line development is used for pyramids and cones in which true length of slant edge or generator is used as a radius.

The plane surfaces (faces of prisms and pyramids) intersect in a straight line. The line of intersection between two curved surfaces (of cylinders and cones) or between a plane surface and curved surfaces is a curve.

The development of lateral surface of a cylinder is a rectangle having one side equal to circumference of its base-circle and or equal to its length. Length is distance between two bases.

As here a prism and cylinder are intersected in which prism has plane surface and cylinder has curved surface and we know curved surface is perpendicular to axis of cylinder and also given solids intersect at 90 degrees so curve formed will be parallel to axis of a prism.

If any of solid in two of intersecting solids is having curves surface that is cylinder, cone, sphere etc line of intersection will give curve only but not straight line for getting line of intersection straight line both solids should not have curved surfaces.