Questions tagged [plane-geometry]

Plane geometry is a subfield of Euclidean geometry, restricted to the flat two-dimensional space. Plane geometry studies shapes, ratios and relative locations of 2D figures which can be embedded in a 2D plane.

Plane geometry is a subfield of Euclidean geometry, restricted to the flat two-dimensional space. Plane geometry studies shapes, ratios and relative locations of 2D figures which can be embedded in a 2D plane.

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The intersection point of bisector of a pyramid

Under which conditions there is an intersection point for all bisectors of a pyramid? A bisector of a pyramid initiating from a vertex is a line which has the same angle with all edges who are neighbor of that vertex.(A natural…
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Can a plane be perpendicular in two other planes if those planes are not parallel to each other?

I have to write equation of a plane which passes through a point and its perpendicular to 2 planes , but before I start solving I was thinking if can a plane be perpendicular to two other planes , if those 2 others are not parallel to each other (…
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How can I tell if a vector is normal (orthogonal) to the plane?

I have to write equation of plane given 2 points $A=(-5,4,2)$ and $B(-3,2,-1)$ and vector $u=(1,2,-3)$. What I did was get a vector from points $A$ and $B$ , $AB=(2,-2,-3)$ and then I found cross product between $AB$ and $u$, $n= AB \times u =…
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intersection of 3 planes

Let $P_1$, $P_2$ and $P_3$ denote, respectively, the planes defined by $$a_1 x+b_1 y+c_1 z= \alpha_1$$ $$a_2 x+b_2 y+c_2 z= \alpha_2$$ $$a_3 x+b_3 y+c_3 z= \alpha_3$$ It is given that $P_1$, $P_2$ and $P_3$ intersect exactly at one point when…
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$\angle ABC = \angle AKC = 90^\circ$, Find length of $BK$.

Diagonal $AC$ of square $ABCD$ coincides with the hypotenuse of right triangle $ACK$. Assuming $B,K$ lie on the same side of $AC$, Prove the following - $BK = \frac{\left| AK - CK \right|}{\sqrt{2}}$ $DK = \frac{\left| AK + CK \right|}{\sqrt{2}}$…
Rezwan Arefin
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Question about proof of Manhattan Minimal Spanning Tree

In this tutorial about line sweep algorithms, there is a section for minimal spanning tree. There is a part that says:- The figure shows the situation in just one of the octants, the West-Northwest one. Q is the closest neighbour (with the dashed…
Cerberus
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Equality and existence proof of a point in a triangle and its areas

Can we always find a point $F$ in the line $BC$ of any triangle such as above so that the triangle $APQ$ is an isosceles triangle and the area of the triangle $AreaAPQ=AreaABC$? It'll be grateful if someone could help me with this. Given $AF$ is…
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A geometry problem based on circles.

Question:- Consider three equal circles $S_1$, $S_2$, and $S_3$ each of which passes through a given point $H$. Other than that, $S_1$ and $S_2$ intersect at $A$, $S_2$ and $S_3$ intersect at $B$, $S_3$ and $S_1$ intersect at $C$. Show that $H$ is…
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Given a plane equation (ax+by+cz=d), how does one find a point on the plane (x0, y0,z0)?

Given a plane equation in the form ax+by+cz=d, how can one find the point (x0, y0, z0)? I already know what the a,b,c,d coeffiecients are. I am not referring to the x,y,z intercepts ie. d=-ax0-by0-cz0 See the example here on…
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Plane Geometry: unit square and traced ray from vertex

The problem: unit square, ABCD. Extend AB as a Ray and trace a Ray from D, crossing the side BC at E and the Ray AB at F. EF = 1. What is the length of BE? (Image attached to scale) Contructed problem to scale This problem is "easy" to…
J.P.
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Longest and Shortest Medians

Is it true for every triangle that the longest median is to the shortest side and the shortest median is to the longest side?
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Coordinate geometry dividing the plane by pairwise straight line

Three pairwise straight line intersecting (but not at the same point) by how many parts these lines divides the plane?
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How to transform plane equation

I have the following mapping from R3 -> R3: Vector3 f(Vector3 v) { // Only points with |x| < z and |y| < z and 0 < z <= SomeConstant are of interest assert(abs(v.x) <= v.z); assert(abs(v.y) <= v.z); assert(v.z > 0); assert(v.z <=…
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What's the value of the segment $MN$ in the figure below?

For refrence: In the figure shown: H ➔ Orthocenter of $\triangle$ ABC; also: BH = 16, AC = 30 and BN = NC Find: MN An important property that can be useful: $OG = 2BH \therefore BH = 8$ Tracing the circumference circumscribed to the triangle…
peta arantes
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Predict Collision Between 2 Uniform Circular Motion Objects

this is my first question on the forum and my algebra is rusty so please be indulgent ^^' I want to predict collision between two uniform circular motion objects for which i know velocity (angular speed in radian), distance from the origin (radius),…
despe
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