Question

the perimete of an equilateral
triangle is81 finds its area​

Answer 1

Answer:

Given Perimeter

Perimeter of equilateral triangle

=3 ×SIDE

3×SIDE =81

SIDE =81/3

SIDE =27UNITS ========>1st equation

AREA OF EQUILATERAL TRIANGLE

= $\frac{ \sqrt{3} }{4} {side}^{2}$

Then

Substitute equation 1 in formula

$\frac{ \sqrt{3} }{4} {27}^{2}$

(729(3)^1/2)/4

Hope It may help you

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Answer 2

Answer:

${\sf{ {\dfrac{729 {\sqrt{3}} }{4}}}}$

Step-by-step explanation:

Given : Perimeter of equilateral triangle = 81 units

• Perimeter of equilateral triangle = 3(Side of equilateral triangle)

Let the side of the equilateral triangle be x unit.

• Putting known values in the above formula.

→ 81 = 3(x)

→ x = 81/3

→ x = 27

Hence, the side of equilateral triangle is 27 units.

Now, the area of the equilateral triangle is :

• Area of the equilateral triangle = ${\sf{ {\dfrac{ {\sqrt{3}} }{4}} \times (side)^2 }}$

• Putting known values in the above formula.

→ Area = ${\sf{{\dfrac{ {\sqrt{3}} }{4}} \times (27)^2 }}$

→ ${\boxed{\sf{ Area = {\dfrac{729 {\sqrt{3}} }{ 4}} }}}$

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♦ In equilateral triangle, all sides are equal.

There are mainly three types of triangle :

• Scalene triangle
• Isosceles triangle
• Equilateral triangle