Question 1181337

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if “Two of the sides”  means side of the base {{{a}}} and {{{L}}} is slant height {{{s}}}

then we need height {{{h}}}

using Pythagoras theorem

{{{h=sqrt(L^2-(a/2)^2)}}}

{{{h=sqrt(20^2-(18/2)^2)}}}

{{{h=sqrt(400-81)}}}

{{{h=sqrt(319)}}}

{{{h=17.86}}}


then 

{{{V=(1/3)a^2*h}}}

{{{V=(1/3)18^2*17.86}}}

{{{V=(1/3)324*17.86}}}

{{{V=108*17.86057109949175}}}

{{{V=1928.94ft^3}}}