What solid figure has 11 faces?

Answer 1

i think it's a cone

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No, it cannot be a cone. But there are a number of possibilities:

A decagonal pyramid = a pyramid whose base is a decagon.

A nonagonal prism = a prism whose bases are nonagons.

A pentagonal pyramid + pentagonal frustum = two pentagonal pyramids stuck together along their pentagonal bases and with one of the apices (plural of apex) cut off.

A cuboid with three corners cut off.

et cetera.