The formula is: 0.5*(n2-3n) = number of diagonals when n is the number of sides of the polygon
A regular 12 sided dodecagon has 54 diagonals.
A dodecagon has 1/2*12*(12-3) = 54 diagonals.
6
There are 54 diagonals in a 12 sided shape
i think it is 54
54
A undecagon has 44 diagonals. A dodecagon has 54 diagonals. An octagon has 20 diagonals. A heptagon has 14 diagonals.
it's a 12 sided shape and it has 54 diagonals :D
a triangle has three diagonals as well as three sides
It is: 0.5*(144-36) = 54 diagonals
12-3 = 9
0 they have no diagonals