# How to find the height of the triangular prism?

So I already know how to calculate base area given all 3 edges. I need to use Herom Formula. Now I'm left with finding the height of the prism. What formula should I apply here to find the height of the prism given that I already have surface area of 1620cm (Sqr) and base area of 360cm(sqr) ? Pic of the prism:

Express the surface area by the height of the prism to have an equation. Note, for example, that the quadrilateral $A_1B_1BA$ is a rectangle (which I assume from the image).
• @Limpuls: Let $h$ be the height of the prism. Then, you can have $1620=2\times \text{(the area of the triangle)}+25h+29h+36h$. Then solve this for $h$. – mathlove Nov 19 '15 at 15:03
• @Limpuls: The equation you wrote is the same as the one I wrote where $H=h$ represents the height of the prism. The 1620 comes from the surface area. The 360 represents the area of the triangle. We have two triangles, so $2\times 360$. $90H$ comes from $25H+29H+36H$ where $25H$ represents the area of the rectangle $A_1B_1BA$ and so on. Note that we have three rectangles $A_1B_1BA, B_1C_1CB$ and $C_1A_1AC$. I hope this helps. – mathlove Nov 19 '15 at 15:17