Question

Find the side of an equilateral triangle whose perimeter is 78 cm

Answer 1

$\huge\rm\green{an{\mathfrak{S}}wer:}$

${}$

$\bf{{\underline{Given}}:}$

• Perimeter of the equilateral triangle is 78cm

$\bf{{\underline{To~find}}:}$

• Side length of the equilateral triangle

$\bf{{\underline{Solution}}:}$

• We know that, all the sides in an equilateral triangle are equal

$\sf\therefore{Let~the~sides~be~~‛x’}$

$\sf{:\implies x+x+x=78cm}$

$\sf{:\implies 3x=78}$

$\sf{:\implies x={\dfrac{78}{3}}}$

$\sf{:\implies {\green{\underline{\boxed{\bf x=26cm}}}}}$

$\bf\therefore{{\underline{Required~answer}}:}$

• The side length of the equilateral triangle is $\sf{\green{\underline{\underline{\bf 26cm}}}}$

Answer 2

Concept

✏️Here the concept of Perimetre of polygon is used. The side of the equilateral triangle is given to us as 78 cm. We have to find the side of the equilateral triangle.

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solution

we know that

• the sides of equilateral triangle are equal.

• All the angles in an equilateral triangle is 60°

Let's do it now

Let us assume the unknown sides of equilateral triangle as x.

Now,

♣ The perimetre of triangle is given as sum of all sides.

$\sf{ \implies x + x + = 78} \\ \\ \sf{ \implies 3x = 78} \\ \\ \sf{ \implies x = \frac{78}{3} } \\ \\ \sf{\implies \color{green}x = 26 \: cm}$

$\mathtt{\therefore the \: sides \: of \: equilateral \: triangle \: is \: 26 \: cm.}$

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More to know !!

⚡ isosceles triangles- Triangle in which 2 sides are equal.

⚡scalene triangle- triangle in which all three sides have different lengths.

⚡right triangles- Triangle having one angle as 90°.

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