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One side of an equilateral triangle is 6in. Find the area of the trianlge.?

17 Answers

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  • 1 decade ago
    Favorite Answer

    Using 30-60-90 degree special triangle properties,

    height = 3sqrt(3)

    area = (1/2)(6)[3sqrt(3)] = 9sqrt(3) units^2

  • DWRead
    Lv 7
    1 decade ago

    Divide the triangle into two 30-60-90 triangles. The sides of a 30-60-90 triangle have the proportions 1:2:√3, so these triangles have sides 3, 6, and 3√3.

    Area of both triangles is base times the height, or

    9√3 in²

    http://www.flickr.com/photos/dwread/3606698791/

  • 1 decade ago

    An equilateral triangle is divided into two equal right triangles by dropping an altitude from any vertex to the opposite side. The hypotenuse of each right triangle is a side of the equilateral triangle, and one leg will be half of a side, so the altitude can be expressed as:

    h = sqrt(s^2 - (s/2)^2) = sqrt(3s^2/4) = s*sqrt(3)/2 using the formula for the area of a triangle A = bh/2 and substituting we have:

    A = s * s * sqrt(3)/4 = 6 * 6 sqrt(3)/4 = 9sqrt(3) = 15.59 sq. inches.

  • Anonymous
    1 decade ago

    Since its an equilateral triangle all sides are 6in and all angles 60

    height^2=6^2-3^2=36-9=27=9*3

    height=3sqr3

    Area=6*3*sqr3*1/2=9sqr3=15.6

    The area is 15.6 square inches

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  • Anonymous
    1 decade ago

    Area = 0.5absinC

    That is the sin of one of the angles times by the remaining sides i.e the sides that are not opposite the angle 'C' hence the reason for know 'c'.

    Dont really have to worry about this for equalateral triangle for obvious reasons

    So it would be

    Area = 0.5 x 6 x 6 x sin60

    = 15.588 In (3dp)

  • 1 decade ago

    since the triangle is equilateral all angles are 60 degrees

    area= 1/2 x 6 x 6x sin60deg =15.6 in^2

  • 1 decade ago

    You need to use trig to find the height of the triangle, which is 6*sin(60) because the adjacent side is length 60 and the angle is 60.

    6*sin(60)=6*sqrt(3)/2=3*sqrt(3)

    Now, use A=1/2b*h = (1/2)*(6)*(3sqrt(3)) = 9 sqrt(3) square inches.

  • 1 decade ago

    area of equilateral triangle = (square root of 3)/4 x (a)square

    where a=6in

  • 1 decade ago

    if one side is 6in then all sides are 6in

    Herons Formula is a formula for working the area of a triangle where all 3 sides are known

    it is :

    A=sqrt(s(s-a)(s-b)(s-c))

    for all triangles abc

    where s=(a+b+c)/2

    so in this case the answer is:

    s=(6+6+6)/2=9

    A=sqrt(9(9-6)(9-6)(9-6))

    =sqrt(9(3)(3)(3))

    =sqrt(243)

    =9root3 in^2

  • 1 decade ago

    the area of an equalaterla triangle is the square root of 3 multiplied by the side squared, then that answer divided by 4

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