 Hello everyone, I am Rahul Patil, Assistant Professor, Department of Mechanical Engineering, Walchand Institute of Technology, Solapur. Today we will discuss about projection of triangular plane. At the end of this session, students will be able to draw the projection of triangular plane. Now, consider the question, a 3060 z square is its shorter side of 50 mm length in the HP. The plane is inclined such that its top view is an isosceles triangle with the shortest side 40 degree inclined to the VP. Draw the projection of a plane and find its inclination with HP. Now read the problem and note down the given data. Here 3060 90 z square is given where shortest side is 50 mm length and it is in HP so that its primary position in first stage z square is drawn in the HP. Now shortest size 40 degree inclined to VP. The inclination with VP is drawn, can you answer this question, where is the inclination of VP is appear, inclination with the VP is appear in the HP. Now shortest side 50 mm and is in the HP. Now inclination with the HP you have to draw in VP and inclination with the VP you have to draw in the HP. Here instead of inclination in second stage they have given the case that it is isosceles triangle. In that case you have to draw the isosceles triangle in second case. Now first draw the x y axis name it as x and y then mark VP and HP. Now draw 3060 z square where AB is 50 mm length remember this AB is in 50 mm length this is the z square. Now draw the projectiles from point AB and C for drawing the front view here A and B lie on straight line it is a single line so that single projectile will appear similar way from point C projection is drawn. Here you will get two points A and B on a single projectile similar way point C is appear. Now join A to C this is the front view for first stage it is a line view. Now in second stage instead of angle they have given the condition that top view of the object is isosceles triangle what is isosceles triangle isosceles triangle is that whose two sides are equal so that draw the isosceles triangle in top view that is in HP in second stage for that draw the projectiles from point A and B where you will get directly distance A to B similar distance you have to mark from B to C so that two sides are equal and you will get isosceles triangle in top view. Now project point A and B in front view again in single projectile similar way for point C now how to draw front view for this condition here A to C distance you have to consider you will get this distance measure A to C take into compass from this point A to B cut this projectile which is from the point C so that this distance must be same what is the procedure measure A to C distance for this is the base point from this base point draw cut the this C's projectile you will get this C point and here is the theta you have to find out which is the inclination with the HP now third inclination with the VP is given this inclination side A B is drawn on this incline mark side A B is drawn on this incline mark mark A B C point now draw the projectiles from point A that is here you will get location for point A again point B here point B is on the same axis that is A B you will get second point as a point B again draw the projectile from point C similar way draw the projection from point C intersection point will appear as a point C now join A B B C and A C this is the final stage now answer while drawing all these things remember that at the end you must measure this angle because in question they ask the inclination with the HP here you will get inclination with the HP measure this inclination and write down where you solve the problem remember that instead of inclination with the HP they have directly given the position of triangle A B C that is isocellular triangle from that isocellular triangle you will find out the inclination that is the theme for the problem now total problem is like that where this is 60 30 set square top view is appear as a isocellular triangle from this isocellular triangle you have to find the inclination with the HP in third stage inclination with the VP is get in the HP remember that if inclination with the VP is given you have to draw it in the HP and similar way problem is carried out these are the references thank you