# Surface area and volume of cones

In earlier grade, we learned all about Surface Area and Volume. We were able to understand the importance of knowing how to compute for these two dimensions. It’s highly applicable in so many things. In fact a video made by the Government of Alberta in Canada was made, explaining how we can use them in real life situations. In this chapter we will review the basic concepts that we tackled on Surface Area back in Grade 8, like the formula for prisms and cylinder.

2.1 will be discussing about how to compute for the surface area and the volume of a prism. From the concepts we learned from grade 8, we know that there are two kinds of prism: rectangular and triangular prism. The surface of area and the volume of the rectangular prism can be computed with the formulas which can be found in the formula sheet of prism and applying our knowledge of the Pythagorean Theorem especially with the triangular prism.

In this chapter we will be looking into other 3D shapes like the Pyramid we will be meeting new terms like slant height, which simply refers to the line bisecting the base of the lateral face of a triangle and ends in the apex.

In 2.2, we will also discuss on how to solve for its surface area and volume through using the formulas B2 (area of the square) + 2BS (area of the 4 triangular sides) and LWH/3 respectively.

2.3 would just a review of what we have learned on Surface Area in Grade 8, where we used the formulas $2\pi r^2$+ $2\pi rh$ and $\pi r^2h$ to solve the surface area and the volume respectively.

Apart from the pyramid, we would also be learning about the cones and the spheres in the last two chapters. The formula for the Surface area of the sphere is $4\pi r^2$, while its volume can be computed by using 4/3($\pi r^3$). The Surface Area of a cone is computed using $\pi rs$ + $\pi r^2$ and the volume is 1/3 ($\pi r2h$).

### Surface area and volume of cones

We just learned how to calculate the surface area and volume of pyramids and cylinders in the previous lessons. Now, we will look at cones ? objects that have circle bases like cylinders and pointy tops like pyramids. Just like pyramids and cylinders, there are formulas for surface area and volume of cones. We will also try out some questions on composite solids that consist of cones too.