Question 1091209
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The base of this pyramid at the plane y = 0 is an isosceles right-angled triangle with the legs of the length of 6 units.


So, its area is {{{(1/2)*6*6}}} = 18 square units.


The height of this pyramid is y-intercept and, therefore, has the length of 3 units.


Therefore, the volume of the pyramid is {{{(1/3)*18*3}}} = 18 cubic units.
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Solved.