Question

find the area of an equilateral triangle whose side is 9 cm.
*should be done by herons formula*
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Answer 1

Answer:

no ...

We should do this question by the formula of equilateral triangle =√3s2/4

√3×9×9/4

Answer 2

Answer:

a=b=c=9 cm

s= 9+9+9/2 cm

= 13.5 cm

Area = √s(s-a)(s-b)(s-c)

= [√13.5(13.5-9)(13.5-9)(13.5-9)]cm²

= [√13.5*4.5*4.5*4.5] cm²

= [√1,230.1875] cm²

= 35.0740289 cm²