Question

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Answer 1

every equilateral triangle, the length of altitude always=1/2*side*sqrt(3). So, if given the length of altitude = 15, it means :
1/2 * side * sqrt(3) = 15
let the length of each side of the triangle is x, so the expression algebraic for this can be :
1/2 * x * sqrt(3) = 15
solve for x

Answer 2

after u got x, to determine of the perimeter, just multiply by 3

Answer 3

well, @Figureskater120 . look at this, how to find of x :
1/2 * x * sqrt(3) = 15
multiply by 2 to both sides, gives us :
2 * 1/2 * x * sqrt(3) = 2 * 15
x * sqrt(3) = 30
now, divided by sqrt(3) to both sides :
x * sqrt(3) / sqrt(3) = 30/sqrt(3)
x = 30/sqrt(3)
here, we need to rationalizing of it :
x = 30/sqrt(3) = 30/sqrt(3) * (sqrt(3)sqrt(3)) = 30sqrt(3)/3= 10sqrt(3)

Answer 4

can u determine the perimeter, now ?

Answer 5

read, my the 2nd coment in the last sentence... ^

Answer 6

exactly, that's right