triangles

A triangle is a polygon with three angles and three sides. We can classify them:

- According to their sides:

   · Scalene: no equal sides

   · Isosceles: two equal sides

           

   · Equilateral: three equal sides

   

- According to their angles:

   · Acute: three acute angles (less than 90^o)

     

   · Right-angled: one right angle (90^o)

    

    · Obtuse: one obtuse angle (more than 90^o)

          

 

 

Exercise: classify these triangles:

a)

b)

c)

 

 

 

Solutions: a) Scalene obtuse triangle; b) Isosceles right-angled triangle; c) Equilateral acute triangle