A circle, an ellipse, a triange, any regular polygon with an odd number of sides, a general (ie not a special case) quadrilateral, are some examples
three
No. A triangle can never have parallel lines. Parallel lines run alongside each other, so that if they continued forever, they would never meet, such as the top and bottom of a square. All lines meet in a triangle. A right triangle is distinguished by having one 90 degree angle (also known as a right angle).
A triange can be of any size
Pyramid
A circle, an ellipse, a triange, any regular polygon with an odd number of sides, a general (ie not a special case) quadrilateral, are some examples
1
Yes
width x highest point on the triange then divide by 2 if equilateral/isoceles triange height x width then divide by 2 if right angled triange/scalene triangle
three
a cone
No. A triangle can never have parallel lines. Parallel lines run alongside each other, so that if they continued forever, they would never meet, such as the top and bottom of a square. All lines meet in a triangle. A right triangle is distinguished by having one 90 degree angle (also known as a right angle).
a triange
180 degrees
== ==
a scalene triangle
1/2 base * height