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,
AD2 + BD2 = AB2
⇒ 42 + (1/2 AB)2 = AB2
⇒ AB2 + 1/4 AB2 = 42
Hence, sides of triangle are 3.6 cm
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