Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [triangles]

For questions about properties and applications of triangles.

A triangle is a polygon with three sides. It is an important geometric figure, because any polygon can be subdivided into triangles.

Triangles can be classified by the number of sides they have that have equal length

  • All three sides of an equilateral triangle have equal length.
  • An isosceles triangle has at least two sides of equal length.
  • A scalene triangle is a triangle that is not isosceles, that is, it has no sides with equal length.

A triangle may also be classified by describing its angles. A triangle is said to be a right triangle if it contains a right angle, and obtuse triangle if it contains an obtuse angle, or an acute triangle if all three of its angles are acute.

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$10.5''$ and $32''$ hypotenuse, $a=8.5$, $b=42.5$, what angles are the $10.5''$ and $32''$ Hypotenuse?

I have a ramp that has a concave "kink" in the angle. The first length of the hypotenuse is $10.5''$, the next is $32''$. The triangle is $8.5''$ tall ($a$) The triangle is $42.5''$ long ($b$) How do I figure out what the angles of the two…
Jared
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Angles of a triangle in a non-flat surface

If I draw a triangle in a surface of a ballon then will its angles add up to still $180^{\circ}$? Will this violate the property of triangles if it is not $180^{\circ}$ and what is the reason for its deviation?
Hydrous Caperilla
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Name and Details of relationship of angles

Could anyone tell me what this relationship of angles is called and where I can read more about it? I'm not mathematically strong but simply put, if a line is drawn perpendicular to the hypotenuse of a right angled triangle, that angle between that…
Gavzooka
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Maximum fixed ratio rectangle within triangle.

I’m looking to convert my attic to a home cinema, and I’m trying to work out what the largest size screen I can have in there (taking the roof pitch into account) and I’m scratching my head at what the equation will be... Initially I’m going on…
jezorama
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Why: OC=OB+BC of an equilateral triangle?

Let's suppose that we have an equilateral triangle ABC as complex numbers. Then why is OC = OB+BC? Isn't OC the shortest distance from O to C? OB+BC is longer right?
Stallmp
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Perimeter of triangle given the following conditions

$CF$ is the angular bisector of $\angle ACB$. $AD$ is the perpendicular drawn from $A$ to $BC$. $E$ is the midpoint of $AC$ Here, I have proceeded as follows: since $\angle ACF = \angle FCB$ therefore $\frac{AC}{AM}=\frac{DC}{DM}$; by Pythagoras…
Suresh
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Find the length of the sides in an Isosceles triangle, given its area and perimeter?

How can I determine the length of the sides $b$, and the altitude $h$ of an isosceles triangle given its area $A= 24 \text{cm}^2$ and its perimeter $P= 16\text{cm}$?
ferret96
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Distance between 2 incenters

Let $\triangle{ABC}$ have side lengths $\overline{AB}=3$, $\overline{BC}=5$, $\overline{CA}=7$ and let $D$ be the circumcenter of this triangle. Also, let $E$ be the incenter of $\triangle{ABD}$. $F$ is the incenter of $\triangle{ACD}$. Find the…
A Piercing Arrow
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Solve side & angle of triangle from a median, side and angle

Given a Triangle ABC with 3 Angles ($A, B, C$) and 3 sides ($a, b, c$) and Median $ma$ (from $A$). like image below: Problem 1: If we know Angle $A$, length of median $ma$, and side $a$. Is it possible to find one more side ($b$ or $c$) or angle…
Incpt.Mobis
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Is this triangle possible to draw?

If the triangle must have the following sides: DE = 3cm DF = 8cm EF = 4cm And not taking into consideration anything about the angles. Is it possible to draw such a triangle?
User10029123
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Quality of triangle

I am currently reading a paper called "Indoor Localization for Bluetooth Low Energy Devices Using Weighted Off-set Triangulation Algorithm". Now they use 3 reference points (APs) to triangulate the position of a person. If they find more than 3…
Pascal
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Hypotenuse and perimeter problem

I need help finding the area of a triangle that has a hypotenuse of 6 and a perimeter 14 ,how can I do it ? The cloest I've gotten is that 5=b and 3=a but that would make c=5.8 I've asked around and my professor said that it can be done but I'm…
Daniel Martinez
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where would a triangle point be located?

This is probably not well phrased but I cannot think exactly how to phrase it. If I have a triangle such that the first point is on fixed axis (0,0) and the second point is free to move, where would I find the third point please? The triangle is an…
HugMyster
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Express AB in terms of $a$

Hello i have these question here. Which way should i solve it? I've tried sine theorem but couldn't find it. Given the triangle $\bigtriangleup$$ABC$ with $\angle$$BCA$$=$$\pi/3$, $\angle$$ABC$$=$$a$, $|BC|=$$\sqrt3$. Express $|AB|$ in terms of…
S1RV1V4L
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Obtuse triangles

How many values of the integer k will make the triangle with sides 6, 8 and k obtuse? 6,8,10 is a right triangle therefore if we enlarge the hyp, then the right angle will become obtuse? Isn't it only 10 < k <14? How do I get the others using a…
SuperMage1
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