These angles are created when two straight sides meet at a vertex ... In an acute-angled triangle, all three angles are acute. Produced by ABC Education Studios in collaboration with The ...

Image caption, Isosceles triangles ABC and DEF are not proportionality the same. The base in EF is twice the size as BC. EF ÷ BC = 6 ÷ 3 = 2. The sides DE and DF are three times the size AB and AC.