A triangle is a polygon. It is a closed 3-sided shape made up of straight lines. The ‘tri-’ part of the word triangle means three. A triangle has 3 sides and 3 angles. Interior angles are the angles ...
Use Pythagoras’ theorem to show a triangle is right-angled or to find one side of a right-angled triangle when two sides are known. Make sure you are confident at substituting into and manipulating ...