Q. 14.0( 3 Votes )

# Calculate the length of the sides of the equilateral triangle on the right, correct to a millimetre.

Answer :

The figure is attached below:

An equilateral triangle has all sides of equal length,

i.e.,

AB = BC = AC

AD is perpendicular to BC,

∴ D is the midpoint of BC

⇒ BD = DC = 1/2 BC = 1/2 AB =1/2 AC

Now using Pythagoras theorem,

AD^{2} + BD^{2} = AB^{2}

⇒ 4^{2} + (1/2 AB)^{2} = AB^{2}

⇒ AB^{2} + 1/4 AB^{2} = 4^{2}

Hence, sides of triangle are 3.6 cm

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