Question

Area of an equilateral triangle whose perimeter is 18 cm is _____ sq.cm ​

Answer 1

Answer:

324

Step-by-step explanation:

area of rectangle = side × side

                             = 18 × 18

                             = 324

Answer 2

★ AnSweR :-

Area of an equilateral triangle whose perimeter is 18 cm is 9√3 cm².

★ GiveN ThaT :-

• perimeter of the equilateral triangle = 18 cm

★ ForMulaS UsEd :-

In an Equilateral triangle of side a cm,

$\sf\orange{Perimeter \: of \: the \: Equilateral \: Triangle = 3a}$

$\sf\orange{Area \: of \: the \: Equilateral \: Triangle = \frac{ \sqrt{3} }{4} {a}^{2} }$

★ SoLuTioN :-

According to the condition,

$\sf{As \: 3a = 18 cm}$

$\sf{\therefore\: a = 6 cm }$

Then,

$\sf{Area = \frac{ \sqrt{3} }{4} {(6)}^{2} } \: {cm}^{2}$

$\sf{Area = \frac{ \sqrt{3} }{4} \times 36} \: {cm}^{2}$

$\sf{Area = \sqrt{3} \times9} \: {cm}^{2}$

$\sf\underline\red{Area \: Of \: The \: Equilateral \: Triangle \: = \: 9\sqrt{3} \: {cm}^{2} }$

[9√3 cm² = 15.588 cm² (approx)]

Which is your required answer!!