1. H

    height of equilateral triangle

    It is given that height of equilateral triangle is (root3/2)*side. I know sin 60 = root 3/2 but how did they get the formulae for the height of equilateral triangle.
  2. J

    More equilateral triangles

    This comes from another thread. Specifically, here's the problem:
  3. D

    Equilateral triangles...

    c a b d (look at it as A,B,C,D) A(8,16) and B(15,10) are given. 2 equilateral triangles ABC and ABD are constructed. So AB = AC = AD = BC = BD. Anybody got a relatively quick way of getting C's and D's coordinates? I keep needing a couple...
  4. jonah

    BASIC Program for Viviani's Theorem on the Equilateral triangle

    WARNING: Beer soaked rambling/opinion/observation ahead. Read at your own risk. Not to be taken seriously. In no event shall Sir jonah in his inebriated state be liable to anyone for special, collateral, incidental, or consequential damages in connection with or arising out of the use of his...
  5. H

    equilateral triangle;incentre;circumecentre

    It is given that in an equilateral triangle , inradius = (1/3) *height and circumradius = (2/3)*height. But both inradius and circumradius are perpendicular bisectors in an equilateral triangle and they should be equal. why do we have different formulae for inradius and circumradius?
  6. I

    Proove it is a equilateral Triangle

    a)their images make up a equilateral triangle b)z1z2.z2z3,z3z1 make up a euilateral triangle Image - TinyPic - Kostenlose Bild- und Videospeicherung und gemeinsame Nutzung von Fotos
  7. jonah

    senior moments, equilateral triangle, infinite geometric series and fixation

    Ever notice that mathhelpforum equilateral triangle logo? You know how some things are there but never really paid much attention. Got fixated about that logo for a few days and then after some hard drinking, came to realize that it figured in some problem that I once ran into. Senior moment...
  8. nycmath

    Equilateral Triangle + Square

    The sum of the perimeter of a equilateral triangle and square is 10. Find the dimensions of the triangle of and square that produce a minimum total area. My Work: Perimeter of square is 4x. Perimeter of Equilateral is 3y. Area of square is x^2. Area of Equilateral triangle is...
  9. F

    Prove that triangle is equilateral

    Over the sides of an arbitrary triangle ABC from the outside are constructed isosceles triangles with an angle of 120^o at the top. Prove that the three vertices of this triangles form an equilateral triangle (triangle DFE on picture). Angles: AFC=AEB=BDC= 120^o Thank you.
  10. E

    Equilateral triangle and inscribed circles, mixed polygons, just my favorite...

    There is an equilateral triangle that is shaded except for the inscribed circle smack in the middle. The radius is 8 and I have to find the shaded area's area.
  11. rcs

    the vertex of the triangle to be equilateral

    A triangle has two vertices at ( -a, 0 ) and (a , 0 ). What must be the third vertex of the triangle to be equilateral? Need your help guys. Thanks
  12. D

    Calculating the coordinates of two points of an equilateral triangle with one point

    I need to calculate the coordinates of two corners of an equilateral triangle if I have the coordinates of the center, the coordinates of one corner point, and the distance from the center to a point. This is for a Java program I'm writing, and it's been a while since I did math like this. The...
  13. M

    Triangle Problem (Need help fast, please reply quickly)

    Three wooden equilateral triangles of side length 18 inches are placed on axles as shown in the diagram to the right. Each axle is 30 inches from the other two axles. A 144-inch leather band is wrapped around the wooden triangles, and a dot at the top corner is painted as shown. The three...
  14. M

    Proof that the equilateral triangle incentre and the circumcentre are the same point

    Hello I have a question on my maths assignment I need some help with. The question says - Make a conjecture about the nature of a triangle where the Incentre and the Circumcentre are the same point. Prove your conjecture. I know that its going to be an equilateral triangle, and I think I...
  15. S

    Vertices of equilateral triangle

    If (0,0), (a,11), (b, 37) are the vertices of an equilateral triangle, find the product of a and b.
  16. sluggerbroth

    an equilateral triangle of side s is inscribed in circle of radius r

    express s as a function of r???? book says s(r)=r (sq root 3)
  17. sluggerbroth

    express area of equilateral triangle as function of one side s???

    express area of equilateral triangle as function of one side s???
  18. J

    A triangle is equilateral if and only if the circumcenter and incenter coincide.

    Prove that a triangle is equilateral if and only if the circumcenter and incenter coincide. Definitions: - Incenter is the center of the inscribed circle (incircle) of the triangle, it is the point of intersection of the angle bisectors of the triangle. - The circumcenter of a triangle is...
  19. J

    the impossible equilateral triangle problem

    Hey guys so i have an impossible problem that needs to be solved. So this equilateral triangle's sides are divided into three equal parts. There are lines drawn from the corners of the triangle to the one of the parts divided. Those lines then create a smaller equilateral triangle (shaded area)...