Question

If the perimeter of an equilateral triangle is 9 cm. Then its area is ………….sq. cm.​

Answer 1

Answer:

12

Step-by-step explanation:

Perimeter of a equilateral triangle = 3*side

9=side*3

9/3=side

3=side

Now,

Perimeter of Square =4*side

=4*3

=12

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Answer 2

$\Large{\underline{\underline{\mathfrak{\bf{Question}}}}}$

If the perimeter of an equilateral triangle is 9 cm. Then its area is ………….sq. cm.

$\Large{\underline{\underline{\mathfrak{\bf{Solution}}}}}$

$\Large{\underline{\mathfrak{\bf{\pink{Given}}}}}$

• perimeter of equilateral triangle = 9 cm

$\Large{\underline{\mathfrak{\bf{\pink{Given}}}}}$

• Area of equilateral triangle

$\Large{\underline{\underline{\mathfrak{\bf{Explanation}}}}}$

we know,

In equilateral triangle sides are same ,

So,Let

• Side will be = x

$\small\boxed{\sf{\:perimeter_{eqilateral\:triangle}\:=\:Sum\:of\:all\:sides}} \\ \\ \mapsto\sf{\:9\:=\:x+x+x} \\ \\ \mapsto\sf{\:3x\:=\:9} \\ \\ \mapsto\sf{\:x\:=\:\dfrac{\cancel{9}}{\cancel{3}}} \\ \\ \mapsto\sf{\:x\:=\:3}$

Thus:-

• Side of equilateral triangle = 3 CM

Now, calculate area :-

$\small\boxed{\sf{\:Area_{Equilateral\:triangle}\:=\:\dfrac{\sqrt{3}.(side)^2}{4}}} \\ \\ \mapsto\sf{\:Area_{triangle}\:=\:\dfrac{\sqrt{3}.(3)^2}{4}} \\ \\ \mapsto\sf{\blue{\:Area_{triangle}\:=\:\dfrac{9.\sqrt{3}}{4}\:cm^2\:\:\:\:Ans}}$