Question

which will be the area of an equilateral triangle having side 6 cm​

Answer 1

First Method:

Area of an equilateral triangle = [(a^2)/2]*sin 60.

Here we have a =6 cm,

so the area = [(6^2)/2]*0.866025403

= 15.58845727 sq cm.

Another method:

If the side is 6 cm, the altitude of the equilateral triangle =

(6 sin 60) = 6*0.866025403 = 5.196152423 cm.

So the area of the equilateral triangle = (6*5.196152423)/2 = 15.58845727 sq cm

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Answer 2

Explanation:

Ar£@ ♂f £qu¡|@ter@| Tr¡@πgl£ by heron's Formul@,

Perimeter=(6+6+6)cm

=18cm

Semi Perimeter=18/2cm =9cm..

Sides (a=6cm,b=6cm,c=6cm)

=√s(s-@)(s-b)($-¢)

=√9(9-6)(9-6)(9-6)

=√9×3×3×3

=√3×3×3×3×3

=9√3cm..... Answer...