Question:
Each side of an equilateral triangle is 8 cm. Its area is
(a) 24 cm2
(b) $04 \sqrt{9} \mathrm{~m}^{2}$
(c) $16 \sqrt{3} \mathrm{~cm}^{2}$
(d) $8 \sqrt{3} \mathrm{~cm}^{2}$
Solution:
(c) $16 \sqrt{3} \mathrm{~cm}^{2}$
Let the side of the equilateral triangle be a.
Given:
a = 8 cm
Now,
Area of the equilateral triangle $=\frac{\sqrt{3}}{4} a^{2}=\frac{\sqrt{3}}{4} \times 8 \times 8=16 \sqrt{3} \mathrm{~cm}^{2}$