Third angle projection is in common use in the USA, Canada, and the UK. The rest of the world more commonly uses first angle. There is no inherent superiority of one projection over the other. When you are making drawings that may be used internationally, it's a very good idea to indicate by a small symbolic diagram which projection is in use. This diagram is usually a side and end view of a truncated cone.
always 30 degrees
In first-angle projection, the projectors originate as if radiated from a viewer's eyeballs and shoot through the 3D object to project a 2D image onto the plane behind it. The 3D object is projected into 2D "paper" space as if you were looking at a radiograph of the object: the top view is under the front view, the right view is at the left of the front view. First-angle projection is the ISO standard and is primarily used in Europe.
The cosine rule which is: a2 = b2+c2-2*b*c*cosine A This is used to find the third side of a triangle when the two other sides are known along with the angle between them. Used when the triangle is not a right angle.
A protractor can be used to measure an angle.
because 2nd and 4th angle projection overlap each other
Third angle projection is in common use in the USA, Canada, and the UK. The rest of the world more commonly uses first angle. There is no inherent superiority of one projection over the other. When you are making drawings that may be used internationally, it's a very good idea to indicate by a small symbolic diagram which projection is in use. This diagram is usually a side and end view of a truncated cone.
always 30 degrees
In 1st angle projection the front view will be in the top of the xy plane and the top view will be in the bottom of the xy plane .In 3rd angle projection the top view will be in the top of the xy plane and front view will be in bottom of the xy plane. dis will give a clear view.i hope u know dis... but in 2 angle projection both the views(front and top) will be in the top of the xy plane and in 4th angle projection both the views (front and top) will be in the bottom of the xy plane... since both the views will be in one side of the xy plane, its not possible to draw... both views will merge... to get more clear view, refer any basic engineering drawing book.......
In first-angle projection, the projectors originate as if radiated from a viewer's eyeballs and shoot through the 3D object to project a 2D image onto the plane behind it. The 3D object is projected into 2D "paper" space as if you were looking at a radiograph of the object: the top view is under the front view, the right view is at the left of the front view. First-angle projection is the ISO standard and is primarily used in Europe.
Because in dot product we take projection fashion and that is why we used cos and similar in cross product we used sin
The lateral ankle projection is an X-ray view that shows the side of the ankle joint. It is used to assess for fractures, dislocations, and arthritis in the ankle joint. The patient may need to position their foot at a 90-degree angle to their leg for this projection.
the Mercator projection
True. The projection note for any map sheet identifies the projection system used on the map sheet.
A map projection that is used for sea travel includes the gnomonic projection. This was most often used to find the shortest routes between points on a sphere.
No, a multiview projection is used for developing a multiview drawing. Multiview projections are orthographic projection where the object is behind the plane of projection, and is oriented such that only two of its dimensions are shown.
Look at whether it is acute, obtuse or reflex. Then, look at the acute component of the angle and try to estimate whether it is half a right angle (45 deg), a third (30 deg) or two third (60 deg). If you are good, then you could try estimating "between a third and a half = 35-40 degrees".