+5478 The formula for the volume of a pyramid is:
$${\mathtt{V}} = {\frac{{\mathtt{1}}}{{\mathtt{3}}}}{\mathtt{\,\times\,}}{\mathtt{Ah}}$$ where A is the area of the base and h is the height of the pyramid (perpendicular to the base, not the slant height).
The area of the base for a triangular pyramid would be the area of the triangle, which would be $${\frac{{\mathtt{1}}}{{\mathtt{2}}}}{\mathtt{\,\times\,}}{\mathtt{Bh}}$$ where b is the length of the base of the triangle, and h is the height of the triangle.
Once you find the area of the pyramid's base, substitute that value for A in the first equation above, and multiply it by (1/3) and the height of the pyramid.
This page can help as well:
http://www.mathsteacher.com.au/year10/ch14_measurement/25_pyramid/21pyramid.htm
+5478 The formula for the volume of a pyramid is:
$${\mathtt{V}} = {\frac{{\mathtt{1}}}{{\mathtt{3}}}}{\mathtt{\,\times\,}}{\mathtt{Ah}}$$ where A is the area of the base and h is the height of the pyramid (perpendicular to the base, not the slant height).
The area of the base for a triangular pyramid would be the area of the triangle, which would be $${\frac{{\mathtt{1}}}{{\mathtt{2}}}}{\mathtt{\,\times\,}}{\mathtt{Bh}}$$ where b is the length of the base of the triangle, and h is the height of the triangle.
Once you find the area of the pyramid's base, substitute that value for A in the first equation above, and multiply it by (1/3) and the height of the pyramid.
This page can help as well:
http://www.mathsteacher.com.au/year10/ch14_measurement/25_pyramid/21pyramid.htm
