Question

Find the area of an equilateral triangle whose each side is 7 cm using heron's formula

Answer 1

Hii !!

Here is your answer,,

Let ∆ ABC is an equilateral triangle.

AB = BC = CA = 7 cm

$s = \frac{7 + 7 + 7}{2} \\ \\ s = \frac{21}{2} \\ \\ heron \: formula \: = \sqrt{s(s - 7)(s - 7)(s - 7)} \\ \\ = \sqrt{ \frac{21}{2}( \frac{21}{2} - 7)( \frac{21}{2} - 7)( \frac{21}{2} - 7 ) } \\ = \sqrt{ \frac{21}{2}( \frac{7}{2} )( \frac{7}{2})( \frac{7}{2} ) } \\ \\ = \sqrt{ \frac{7230}{16} } \\ \\ = \frac{84.87}{4} \\ \\ = 21.21 {cm}^{2}$

HOPE IT HELP YOU.

THANKS..

Answer 2

Hi,

Please see the attached file!


Thanks