Question

What is the length of the altitude of the equilateral triangle below?​

Answer 1

Answer:

A

Step-by-step explanation:

the height a creates with half of the baseline (5) and a leg (10) a right-angled triangle, and we can use Pythagoras to calculate a.

c² = a² + b²

c being the Hypotenuse (the side opposite of the 90° angle, so in our case the 10 side).

10² = a² + 5²

100 = a² + 25

75 = a²

a = sqrt(75) = sqrt(3×25) = 5×sqrt(3)