Question

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

Answer 1

Answer:

Perimeter= 18cm

3* side= 18

side=18/3

side of ∆= 6 cm

Area of equilateral triangle=

$\sqrt{3 \div 4} \: \: {side} {}^{2}$

=√3/4 x (6)^2

=√3/4 x 36

=9√3 cm^2

Answer 2

Step-by-step explanation:

Question:-

Find the area of equilateral triangle whose perimeter is 18cm.

Answer:-

Given :-

• The given figure is an equilateral triangle.

• The perimeter of triangle is 18cm.

To find :-

Area of the equilateral triangle

Process :-

As we know that an equilateral triangle has all sides equal and it's perimeter is the sum of all it's sides,so finding one side is only needed.

Then:-

Perimeter = 3 × a (a = each side of the triangle)

⇒18 = 3 × a

⇒ 3 × a= 18

⇒ a = 18/3 = 6

∴ 6cm is the measure of each side of the triangle.

Area of the triangle:-

$Area = \sqrt{\frac{3}{4} } × a² \\ \\ ⇒Area = \sqrt{ \frac{3}{4} } × (6)² \\ \\ ⇒Area = \sqrt{ \frac{3}{4} } \times 36 \\ \\ ⇒Area = 15.59cm$

∴The area of the equilateral triangle will be 15.59cm

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Hope it helps you...

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