Question

the perimeter of an equilateral triangle is 39 centimeters. What is the length of an altitude of the triangle ?​

Answer 1

Answer: $h = 11.26cm$

Step-by-step explanation:

Equilateral triangle has equal sides, let the side be $xcm$ , then the perimeter is $3x$

Therefore:

$3x = 39$

$x = 39/3$

$x = 13cm$

To find the altitude , we will apply Pythagoras theorem , that is

$13^{2}=h^{2}+6.5^{2}$

Therefore:

$h^{2}=13^{2}-6.5^{2}$

$h^{2}=169-42.25$

$h^{2}=126.75$

take the square root of both sides

$h = 11.26cm$