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The circumcentre, centroid and orthocentre of a triangle 2012-04-24
From Nazrul:
The circumcentre, centroid and orthocentre of a triangle is given. The distance between circumcentre and orthocentre is also given. How can I draw the circle? Please Help me.
Answered by Chris Fisher.
The centroid and circumcircle of a triangle 2008-12-09
From prateet:
in an equilateral triangle prove that the centroid and centre of the circumcircle coincide

here i am not clear about the concept of centroid and circumcircle i cant understand how AGis 2/3 AD. please help in details about the topic mentioned.

Answered by Harley Weston.
The centroid of a polygon 2007-12-29
From David:
I am playing around with an idea. I've read previous answers to questions (using surveyor calculation methods) related to finding the area of an irregular shape parcel of land (or irregular polygon). Is there a formula or method for calculating the centroid (mid-point) for this type of polygon. I've seen plenty of methods for calculating the mid-point for a triangle or regular shape poloygon but few for an irregular shape polygon such as a parcel of land. Thanks...
Answered by Harley Weston.
Find the centroid 2007-11-26
From josh:
vertices X(-2,6) Y(4,10) Z(14,6) find the coordinates of the centroid
Answered by Stephen La Rocque.
Return on investment 2007-11-02
From Julie:
Hi - I'm trying to figure out what my ROI ( Return on my investment) is for a particular product I purchased. My investment cost was $4100 and my savings as a result of this investment was $34,170. How can I figure out what my ROI was on this product. Thanks much for your help!
Answered by Penny Nom.
A perpendicular intersection of two barrel vaults 2006-07-21
From Neal:
I'm wanting to build a series of architectural models of different roman and medieval buildings out of cardboard. Once I have perfected the models I want to print them out on card stock so that school kids (or anyone else) can make the buildings.
A feature of many of these models is the cross or groin vault (a perpendicular intersection of two barrel vaults).
A single barrel vault is easy to imagine as a plane (a rectangular piece of cardboard) that will be folded into a semi-circular arch.
The intersection of a second barrel vault and this one is presenting me with problems. The second plane needs to have an ellipse cut into it so that when it is folded into the arch, it will mate up with the curve of the first barrel vault.
Given that the two pieces of card have identical widths (and therefore identical arcs in cross section) is there a way to calculate the ellipse that needs to be cut so that it can be cut before the second arch is folded?

Answered by Edward Doolittle.
The centroid of a triangle 2006-01-18
From Andrea:
I am trying to find the centriod of a triangle. I have been given the three vertices of the triangle: A (-25, -20), B (-5, -40), and C (15, 30). I believe I calculated the correct midpoints: AB(E) (-5, 5), BC(D) (5, -5), and AC(F) (-15, -30). When I graphed these points I came up with the solution (-5, -10), but I can't seem to write the answer out (equations of the lines, etc) correctly. Any help would be greatly appreciated!
Answered by Penny Nom.
The centroid of a triangle 2005-04-07
From Maria:
Q3)find the coordinates of the centroid of triangle ABC i want your help here to solve the 3rd question i got stuck.
Answered by Penny Nom.
Vectors in three space 2004-10-30
From Jo:
I have two questions that I just cannot visulise and dont know how to get started on them..!

1. Ship X is sailing North at 4m/s and Ship Y is sailing due East at 3m/s. A sailor on Ship X climbs a vertical pole at 1/2 m/s. What is the velocity of the sailor on Ship X relative to an observer on Ship Y? State it's magnitude and direction.

Not sure where to start with this one...

2. Show, using vectors, that for any tetrahedron, the segments joining the midpoints of the opposite edges are concurrent. i know what a tetradedron is, and what I am proving but do I solve simultaneously for a specific case??

Answered by Walter Whiteley.
The point where all the medians meet 2004-02-25
From A student:
What's the name of the point where all the medians meet?
Answered by Penny Nom.
A centroid problem 2000-06-02
From Kerstin:
An isoceles triangle has sides measuring 13 cm, 13 cm, and 10 cm. Find the distance from the centroid to the vertex of a base angle.
Answered by Harley Weston.
Two sides and a bisectrix. 1998-11-11
From Victor Grinshtein:
I am looking for someone who can tell me how to construct a triangle by 2 sides and a bisectrix using a compass and a ruler.
Answered by Chris Fisher.
Volumes 1998-08-29
From Lorraine Wall:
Consider the region in the first quadrant bounded by the x and y axes, the vertical line x=3 and the curve y = 1 / (x squared + 3). Determine the volume of the solid by rotating this region about the x-axis. Now that is the first part.
I then have to find the coordinates of the centroid of the solid by rotating this region about the x-axis.

Answered by Harley Weston.

Un système de plusieurs équations et plusieurs inconnues 2009-01-22
From Cédrick:
J'ai un problème écrit à résoudre est-ce que vous pouvez m'aider ?

Le premier est le tiers de la somme des deux autres.
La somme du premier et du deuxième est 13.
Le produit du deuxième et du troisième est 56.
Réponse: Le premier nombre est___________________
Le deuxième nombre est _________________
Le troisième nombre est _________________

Answered by Pierre-Louis Gagnon, Antoine Letarte at Claude Tardif.
Marie achète un croissant et une tartelette 2004-02-01
From M. et Mme Simoneton:
Marie achète un croissant et une tartelette. Elle paie 1,64 €
Isabelle achète un croissant et un pain au chocolat. Elle paie 1,51 €
Marc achète un poain au chocolat et une tartelette. Elle paie 1,77 €
Trouver le prix d'un croissant, d'une tartelette et d'un pain au chocolat.

Answered by Claude Tardif.
Les 3 maisons 2003-11-16
From Amandine:
Sur la figure ci-contre on peut voir 3 maisons A, B et C nouvellement construites. Toutes les 3 doivent être reliées au gaz, à l'eau et à l'électricité. Cependant, tous ces raccordements doivent impérativement avoir lieu dans un même plan et les câbles et autres canalisations ne peuvent pas se croiser. Comment doit-on s'y prendre pour relier les 3 maisons à l'eau, au gaz et à l'électricité?
Answered by Claude Tardif.



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