Question 1077400
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The total surface area in this case is the sum of the lateral surface area and the areas of two bases.


<pre>
1.  The base area is six times the area of one single equilateral triangle with the side length of 12 millimeters.

    The area of one such equilateral triangle is {{{(1/2)*12*((12*sqrt(3))/2)}}} = {{{36*sqrt(3)}}}.

   (12 millimeters is the base and {{{(12*sqrt(3))/2}}} is the height of such a triangle).

   So, the area of two bases is {{{72*sqrt(3)}}} millimeters squared.



2.  The lateral area of the prism is six times the area of one (each) single lateral face, which is a rectangle 
    with dimensions 12 millimeters and 10 millimeters.



3.  Having these hints you can easily complete the solution on your own.
</pre>


You have this free of charge online textbook on Geometry

&nbsp;&nbsp;&nbsp;&nbsp;<A HREF=https://www.algebra.com/algebra/homework/Triangles/GEOMETRY-your-online-textbook.lesson>GEOMETRY - YOUR ONLINE TEXTBOOK</A> 

in this site.



On surface area of solid 3D bodies see the section <U>Surface area of 3D solid bodies</U> of this online textbook.