Quadrilaterals and Triangles



  • 2-D figure with 4 sides
  • sum of interior angles = 360\degree



  • 3 sides
  • sum of interior angles = 180\degree

Draw one quadrilateral with equal sides but no right angles.


  • 2 equilateral triangles
  • All sides are equal
  • 180\degree\div3=60\degree




Find the size of the third angle of a triangle with angles 73\degree and 49\degree. Then draw a similar triangle to this, but twice the size.


Similar – figure with same shape but not the same size








* triangle not to scale, approximate