Well, isn't that just a happy little question! To determine the 18th shape in a triangle, square, and circle, you can start by looking at the pattern of shapes. Each shape adds one more side than the previous one, so the 18th shape would have 18 sides. Just remember, there are no mistakes, only happy little accidents in math and art.
a circle or a triangle
its a triangle, circle,
Scalene triangle
A circle !!!!!!
It is the circle that does not belong to the given shapes.
circle triangle square
a circle or a triangle
Circle, triangle, square, circle, square.
A circle, or a scalene triangle.
its a a combination of a 3D circle and triangle
triangle,circle and a star
its a triangle, circle,
Scalene triangle
It is the circle that does not belong to the given shapes.
A circle !!!!!!
A circle can.
an upper triangle no not really spike its a circle