Question

Find the length of altitude of an equilateral triangle having side 2a.​

Answer 1

In ΔABD,
(AD)
2
=(2a)
2
−(a)
2

(AD)
2
=4a
2
−a
2
=3a
2



​

Answer 2

In ΔABD,

(AD)^2=(2a)^2−(a)^2

(AD)^2=4a^2−a^2=3a^2

AD=√3a.