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 :
$$\begin{array}{rl}& =\left(\frac{\sqrt{3}}{4}\times 1^2\right)m^2\\ & =\frac{\sqrt{3}}{4}{m}^2\end{array}$$
∴ Volume of pyramid :
$$\begin{array}{rl}& =\left(\frac{1}{3}\times \frac{\sqrt{3}}{4}\times 4\right)m^3\\ & =\left(\frac{\sqrt{3}}{3}\right)m^3\\ & =\left(\frac{1.732}{3}\right)m^3\\ & =0.577m^3\end{array}$$