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The number of diagonals that can be draw...

The number of diagonals that can be drawn by joining the vertices of an octagon is `20` b. `28` c. `8` d. 16

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An octagon has 8 vertices.
The number of diagonals of a polygon is given by `frac{n(n-3)}{2}`
`therefore` Number of diagonals of an octagon
`=frac{8(8-3)}{2}=20`
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