Question
The base of a pyramid is an equilateral triangle of side 1 m. If the height of the pyramid is 4 metres, then the volume is :
Answer: Option B Area of the base :
$$\eqalign{
& = \left( {\frac{{\sqrt 3 }}{4} \times {1^2}} \right){m^2} \cr
& = \frac{{\sqrt 3 }}{4}{m^2} \cr} $$
∴ Volume of pyramid :
$$\eqalign{
& = \left( {\frac{1}{3} \times \frac{{\sqrt 3 }}{4} \times 4} \right){m^3} \cr
& = \left( {\frac{{\sqrt 3 }}{3}} \right){m^3} \cr
& = \left( {\frac{{1.732}}{3}} \right){m^3} \cr
& = 0.577\,{m^3} \cr} $$
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