If the length of one side of an equilateral triangle measures 40 cm, what is the length of its altitude? State the letter of the correct answer.

the length of its altitude is 34.64 cm

Step-by-step explanation:

Given;

length of a side of the equilateral triangle, L = 40 cm

All the sides of an equilateral triangle are equal

To get the altitude of the triangle, draw a perpendicular line from one of the vertices to intersect the opposite side.

Let the altitude = h

half of the opposite side intersected by the altitude = 20 cm

Apply Pythagoras theorem to determine the altitude 'h'

h² = 40²  -  20²

h² = 1200

h = √1200

h = 34.64 cm

Therefore, the length of its altitude is 34.64 cm