Answer:
3√3 units
Step-by-step explanation:
We are asked to find the altitude of the equilateral triangle whose perimeter is 18 . Firstly let us find the side of the∆.
[tex]\rm \implies a + a + a = 18 \\\\\rm\implies 3a = 18 \\\\\rm\implies a = 6 [/tex]
Now we know that in a equilateral triangle , the altitude of the triangle with side length a is ,
[tex]\rm\implies Altitude =\dfrac{\sqrt3}{2} a [/tex]
Plug in the value of a that is 6 , we will get ,
[tex]\rm\implies Altitude =\dfrac{\sqrt 3}{2} a \\\\\rm\implies Altitude =\dfrac{ \sqrt3}{2}\times 6 \\\\\rm\implies Altitude = \sqrt3 \times 3 \\\\\rm\implies\boxed{ \bf Altitude = 3\sqrt3 \ units }[/tex]
