The volume of the pyramid is B. 567in^{3}.

Step-by-step explanation:

The volume of a pyramid is calculated using the following formula

V = frac{lwh}{3}

In which L is length of base, W is width of base, and H is height of the pyramid. Since the base of a pyramid is a square (which have 4 equal sides) and we were given the length and height we can plug that into the formula to get the volume of the pyramid.

V = frac{(9in)(9in)(21in)}{3}

V = frac{(81in^{2})(21in ) }{3}

V = frac{1701in^{3} }{3}

V = 567in^{3}

So the volume of the pyramid is 567in^{3}.

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