Each side of an equilateral triangle is 10 cm long. The height of the triangle is –

We have,

Each side of the equilateral triangle = 10 cm

We know that,

In an equilateral triangle altitude divides its base into 2 equal parts

∴

Let the height be h

Now, by using Pythagoras theorem

10^{2} = 5^{2} + h^{2}

100 = 25 + h^{2}

h^{2} = 100 – 25

h^{2} = 75

h =

h = 5 cm

Hence, height of the triangle is 5 cm

Thus, option (b) is correct

7