How many right angles in a cylinder.
I say infinity and she says 0. Can anyone help me, please
Thanks
Phil
2007-10-01 05:41:07 · 25 answers · asked by phil b 1 in Education & Reference ➔ Homework Help
Thanks you all for your responses. To elaborate further, The homework is to draw a shape in 2d and then in 3d. My wifedecided to pick a square, rectangel, triange & circle. The problem can when we were tranferring them to 3d, and annotate sides, vertices and right angles.
Obviously had no problem with the square, rectangle and triangle, but when my wife helped her with the circle, i helpfully added that there would be infinite right angles as the to planes of the shape meet at the bottom in a right angle.
My wife & I (!!) then had a discussion and i googled it, but with no joy so thought i would ask you lot !
(Maybe we whould have rubbed uit out and added a pentagon !)
Thanks for you help thought
2007-10-01 07:23:52 · update #1
Well, we know there are at least some, since the two "ends" of the cylinder - the circles - are perpendicular to the "walls" of the cylinder. [This assumes a right regular cylinder.]
So I would agree with you that the answer is infinity. If you pick a point on the surface "wall" of the cylinder, and draw a line to the center of either of the circle "ends," you will have a 90-degree angle, and vice versa.
Interesting question!
2007-10-01 05:45:42 · answer #1 · answered by Anonymous · 1⤊ 1⤋
I would say infinity also but it depends on the shape of the cylinder.
go to http://www.cliffsnotes.com/WileyCDA/CliffsReviewTopic/Right-Circular-Cylinders.topicArticleId-18851,articleId-18834.html
I know there is at least 1 if it is a right circular cylinder (imaginary line down the center and out to the edge). Rounded edge doesn't mean that the line has to be rounded too, that's an optical illusion. Everything is made of lines. The above link will probably help you visualize it best.
I think many of these people are confusing a cylinder with a "sphere" which would not have any right angles.
2007-10-01 05:43:59 · answer #2 · answered by Lollipop 5 · 2⤊ 0⤋
If it is a regular cylinder, it will have a 90 degree angle where the side meets the base.... which leads to the infinity answer.
By the way -- There is absolutely NO chance that a seven year old would have to answer a question like this.
2007-10-01 06:06:33 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Infinity. A cylinder is a solid of revolution of a rectangle, ie. when the rectangle is revolved about one of its sides, we get a cylinder. That implies there are infinite such rectangle constituting a cylinder giving you infinite right angles.
2007-10-01 05:47:59 · answer #4 · answered by *Felicia* 4 · 1⤊ 0⤋
A cylinder is 3D and a right angle is two lines on the same plane (2D). Though the intersection of a plane and a cylinder can create 2D right angles, the 3D cylinder alone has no right angles.
2007-10-01 05:47:58 · answer #5 · answered by Level 7 is Best 7 · 0⤊ 2⤋
The base and the sides are at right angles and since the number of planes that are perpendicular to the base is infinite, you are right.
2007-10-01 05:45:24 · answer #6 · answered by Swamy 7 · 3⤊ 0⤋
Why would you say that? Then if you are right all imaginable circular shape figure in geometry got endless right angles...?
I'm lined with your 7 y.o.
2007-10-01 05:47:59 · answer #7 · answered by triximetric 3 · 0⤊ 0⤋
plan view 360 then 4 better check a book
2007-10-01 05:44:18 · answer #8 · answered by Freg A 2 · 1⤊ 0⤋
i think it suppose to be 0. the cylinder has no spot like the angle at all....
2007-10-01 05:44:55 · answer #9 · answered by Anonymous · 2⤊ 1⤋
Just google your questions anytime you get stuck. It has helped me greatly. You could also look up homework tutorials. There are tons of websites for that too.
2007-10-01 05:44:24 · answer #10 · answered by lpogue2005 3 · 1⤊ 1⤋