Right-angled.
A scalene triangle
An acute angled scalene triangle.
It is an equilateral triangle
An obtuse triangle is a type of triangle that has no congruent sides. Basically none of its sides are the same size.
The name of a triangle is dependent on the type of angles within it. If it has a right angle it is called a right triangle, if it has an obtuse angle it is an obtuse triangle, and if all three sides are acute it is an acute triangle.
An acute angled triangle.
Any kind of triangle can have rational or irrational sides: acute angled, right angled or obtuse angled; equilateral, isosceles or scalene.
An acute angled triangle.
An Acute Triangle
Isosceles is a type of triangle that has at least two sides and two angles equal. An acute isosceles has one angle less than 90 degrees.
An Isosceles Triangle.
A triangle can have only three sides. No triangle can have 9 sides!