







Can you construct a regular 21gon? 
20160308 

From Peter: hi, i know that if i use a compass to draw a circle, i can use the same setting to mark 6 intervals along the circle circumference, how would i go about marking out 21 equally spaced points around the circumference?
if there an online calculator i can us, or some other interesting trick?
tia
peter Answered by Robert Dawson. 





The volume of a wedge 
20140521 

From steve: I need to figure the volume of a wedge / right triangle, the dimensions of the right triangle is L1(10'5"), L2 (10'6"), H (14'9.5") height of L1 is 0'0" height at intersect L2/H is 3'3" Answered by Penny Nom. 





How many edges does cone have? 
20130128 

From Meriem: how many edges does cone have pls? Answered by Lorraine Dame, Chris Fisher and Walter Whiteley. 





The volume of a wedge 
20120528 

From olwethu: volume of wedge that have side 3,3 cm and 6,2 cm and 20 cm long? Answered by Penny Nom. 





6 faces and 8 corners 
20110304 

From noemi: jeff made a figure with 6 faces the figure has 8 corners all of the faces are the same size and shape what figure did jeff make Answered by Penny Nom. 





Vertices and sides of a polygon 
20110304 

From RINA: My questions is : would a vertices and sides of a polygon be the same number. For example, a octagon it has 8 points and 8 sides. Am i correct? Answered by Robert Dawson. 





The area of a field of view 
20100407 

From Frank: I know we have a field of view of 90 degrees and the distance we can cover is 6 miles. What is the area we can cover/view?
A formula would be nice to have since the diameter or distance of the wedge area can change and the degree of the field of view can also change.
Thank you and I look forward to hearing from you.
Frank Answered by Penny Nom. 





A triangular pyramid 
20100105 

From ally: how many vertices, edges, faces in a triangular pyramid? Answered by Robert Dawson. 





How high is the ledge? 
20091003 

From gabby: Standing on a ledge, there is a boat 25 degrees below you. The boat has a 1,000ft. tower. If the angle of elevation to the top of the tower is 15 degrees, how high is the ledge? Answered by Stephen La Rocque. 





A simple digraph 
20090323 

From Shabkhal: Show that the sum of in degrees of all the nodes of a simple digraph is equal to the sum of out degrees of all its nodes and this sum is equal to the number of edges of the graph. Answered by Victoria West. 





A triangular pyramid 
20090226 

From Craig: Can you help with this question:
Write the names of the faces and the number of each kind of face on a triangular
pyramid? Answered by Penny Nom. 





Vertices, edges and faces 
20090219 

From Deb: I have been reading the responses you have to whether or not a cone and cylinder have edges, and whether a cone has a vertex. I have also found differing answers in different books and websites. Your idea that it depends why we want to call it a vertex or edge is interesting but does not help the students next year when they have a different teacher who tells them that whatever decision I make is wrong! It also doesn't help them when they do the provincial testing. Does anyone know if EQAO considers them vertices or edges? I want to know because textbooks and provincial tests often ask the students to count the number of faces, edges, and vertices or to describe a solid by using these, or to identify a solid that they have described. We need to have consistency in what we are teaching! Answered by Chris Fisher. 





Faces, edges and vertices 
20090204 

From sheila: what is the relationship between the number of faces and the number of edges of a triangular pyramid ? Answered by Penny Nom. 





The volume of a slice from a wedge 
20081016 

From Jeff: If I have a wedge shaped object (ie, a triangle of nonspecific type
extruded along a length) and it is sliced from the twocorner base at
one end to the onepoint tip at the other, what is the volume of the
upper (smaller) part as a percentage of the whole? I hope I have
explained it clearly enough. Thanks. Answered by Harley Weston. 





Does an oval have sides? 
20081002 

From reid: My 6 yo neice came home with her math homework and she was supposed to identify which objects had sides.One of the objects was an oval.I don't believe it has sides because it is curved and I don't think that would make it an object with sides.What would be the correct answer?Thanks,Reid Answered by Janice Cotcher. 





Angles in a regular tetrahedron 
20080807 

From Carla: Hi guys,
A regular tetrahedron has all its edges 8cm in length.
Find the angles which an edge makes with the base.
Thanks.
Carla Answered by Penny Nom. 





Finding Angles in a Pyramid 
20080730 

From Carla: A pyramid has its vertex directly above the centre of its square base. The edges of the base
are each 8cm, and the vertical height is 10cm. Find the angle between the slant face and the base,
and the angle between the slant edge and the base. Answered by Janice Cotcher. 





A shape 
20080403 

From Joshua: what shape has 4 faces, 4 corners and 9 edges. Answered by Penny Nom. 





Some solid figures 
20080228 

From tiffany: What solid figure could have? It has 4 more edges than vertices, Answered by Penny Nom. 





Dividing a segment into 3 congruent parts 
20071030 

From Carolyn: I am doing construction. I have a line segment drawn. I need to divide a segment into 3 congruent part. How do I do that? Answered by Penny Nom. 





A triangular pyramid 
20070722 

From shani: my homework question is confusing (yr 7 beginner)
"How many vertices does a triangular pyramid have."
(Mum thinks all triangles are triangular& vertices are sides)
I want to be sure. Answered by Penny Nom. 





Hexagonal pyramids 
20070517 

From Tracey: How many faces, edges, and vertices does a hexagonal pyramid have? Answered by Stephen La Rocque. 





What's a vertex? What's an edge? 
20070516 

From Sophie: I don't understand what is a vertex and what is an edge. Please put a picture up and explain. I am a fifth grader. Answered by Brennan Yaremko and Steve La Rocque. 





Volume of a wedge 
20070514 

From Mark: We need to fill in dirt along a 75 foot long fence, 3 feet out , statring at 6 inches agaisnt the fence, sloping to 2 inches at the grass. I am trying to calculate the volume to order enough cubic yards of dirt to fill this. Answered by Stephen La Rocque. 





Vertices, edges and faces 
20070419 

From Kimberly: I am trying to help my son find the vertices, edge, and face of a 16 sided figure.
I am not sure of the process to use to find these, could you please tell me
how to do this? Answered by Penny Nom. 





Which solid figure has 4 more edges than vertices? 
20070322 

From dawn: which solid figure has 4 more edges than vertices? Answered by Penny Nom. 





What constitutes a face for a geometric solid? 
20070214 

From Erica: What constitutes a face for a geometric solid? We have been getting conflicting answers from different textbooks. Some teachers are saying that cylinders and cones do not have faces. I'm thinking that cylinders have 2 and cones have 1. Please enlighten me. Thanks! Answered by Walter Whiteley. 





A cylinder has how many flat surfaces, vertices, and edges? 
20070109 

From Stacy: A cylinder has how many flat surfaces, vertices, and edges? Answered by Diane Hanson and Penny Nom. 





Octagonal Stop Sign 
20061023 

From Phil: My colleagues and I are in a discussion about how many true "sides" an octagonal stop sign has. I say that it has 10 true sides because of the front back sides of a stop sign (3D octagon). Is this correct terminology or should the front and back "sides" be referred to as faces  equaling 2? Answered by Paul Betts, Steve La Rocque and Harley Weston. 





Constructing figures 
20050920 

From Kim: I would like to know how to draw different shapes:
Regular Octagon with sides of length, 1 unit
Equilateral Triangles, with sides of length 1 unit
Regular Hexagons, with sides of length 1 unit
Isoseles Triangles, with hypotenuse of length 1 unit
Answered by Penny Nom. 





A 3dimensional pie shape 
20050917 

From Bill: Your site appeared in my search for the name of a 3dimensional pie shape. 2d would be a sector of a circle. As it it curved, I don't believe it is in a the polyhedra family. Can you help me find the mathematical term for it? Answered by Chris Fisher. 





A pyramid 
20040511 

From Quiana: I am a student and I have the following questions I need to answer for homework:
How many sides, vertices, and edges does a pyramid have? Answered by Penny Nom. 





Some shapes 
20030429 

From Suzanne:
 What shape has 12 edges all the same length?
 What shape has 3 surfaces and 1 is curved?
Answered by Penny Nom. 





8 faces, 12 vertices, and 18 edges 
20030422 

From Thomas: I would like to know the proper name for this geometrical solid. It has 8 faces, 12 vertices, and 18 edges? Answered by Penny Nom. 





Construct a pentagon 
20021212 

From Mary: We were wondering what the instructions/formula, stepbystep, is to make a pentagon. Answered by Chris Fisher and Penny Nom. 





Constructing the square root of 3 
20020607 

From Allan: I am a Math 7/8 teacher. I was wondering how you would show a student how to find the exact location of the square root of three on the number line using just a compass and a straight edge. Answered by Penny Nom. 





Logico mathematical knowledge 
20020123 

From A teacher: How does young children's logico mathematical knowledge develop? Answered by Walter Whitely. 





Euler's Formula 
20001111 

From Denise Roberts: I'm trying to design a unit (possibly involving a Webquest) on Polyhedra and I cannot find a formula I once used. The formula involved the number of vertices (V), edges (E), and faces (F) of the polyhedra. Answered by Walter Whiteley. 

