<PRE><B>Question 1133461</B>
(30*10)/2 = 150 each of 3 sides has an area of 150.
Thus:
150*3 =  450 this is the surface area of the top 3 triangles.
Now we need the area of the triangular base, which is an equilateral triangle with sides of length 30. Draw a line perpendicular from one of the vertex to the middle
of the side. Now we have two right triangles with one side 15 and the hypotenuse 30. Pythagoras says:
sqrt(30^2 - 15^2) = 26 this is the height of the triangle.
Area:
bh/2 = 30*26/2 = 390
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Total area:
450 + 390 = 840</PRE>