3. What is the volume of the regular pyramid?

 80 cubic meters (choice B)

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Explanation:

The floor of the pyramid is a pentagon made of five congruent isosceles triangles as shown in the diagram below. Each triangle has a base of 6 meters and height 2 meters. The base and height are always perpendicular.

Each triangle mentioned therefore has area base*height/2 = 6*2/2 = 12/2 = 6 square meters. Five such triangles results in a total area of 6*5 = 30 square meters. This is the area of the pentagonal floor.

We'll multiply this area by the height of the pyramid (8 meters) and then take 1/3 of this to get the pyramid's volume

volume = (1/3)*(area of floor)*(height of pyramid)

volume = (1/3)*(30)*(8)

volume = 10*8

volume = 80 cubic meters

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".

could you provide figure.