The 4 angles in a parallelogram add up to 360 degrees.
An irregular dodecagon.
Yes corresponding angles on the transversal line are equal
complementary angles
An irregular pentagon can have 5 vertices and two right-angles.
6
The interior angles sum to 1980 degrees.
It is 180 :)
In geometry, a triskaidecagon has 13 sides and 13 angles. A triskaidecagon is also called a tridecagon. A tridecagram is a 13-sided star polygon.
This is the problem which comes from trying to be too smart. You should not use Greek prefices if you do not understand them. There is no such thing as a tridecagon: a 13-gon is a triskaidecagon whereas a 30-gon is a triacontagon. Stick to simple forms through which you can communicate rather than try and be pretentious!
A triangle has no diagonals
A tridecagon is a 13 sided polygon. Also called a triskaidecagon.
triskaidecagon or a tridecagon. triskaidecagon or a tridecagon.
A 13 sided polygon is called a Tridecagon also a Triskaidecagon.
A link to a picture of a regular tridecagon (also known as a triskaidecagon), a thirteen-sided polygon, can be found below this answer.
Triskaidecagon or Tridecagon
Tridecagon