©G Dear2010 – Not to be sold/Free to use Congruence Triangles Properties Stage 4 - Year 9 Press Ctrl-A ©G Dear2010 – Not to be sold/Free to use
Two triangles are congruent if they are the same size and shape. Congruent Triangles Two triangles are congruent if they are the same size and shape. There are four Rules Side, Side, Side. Side, Angle, Side. Angle, Angle, Side. Right Angle, Hypotenuse, Side. End of Slide
Prove that the base angles of an isosceles triangle are equal. Isosceles Triangles Prove that the base angles of an isosceles triangle are equal. A B C Add a perpendicular. D ADB = ADC Right Angle AB = AC Hypotenuse AD = AD Common Side ADB ADC RHS ● ● B = C Congruent s End of Slide
Equilateral Triangles Prove that the sides of an equilateral triangle are equal. Add a bisector. A B C 60o B = C Given Angle D ADB = ADC Right Angle AD = AD Common Side ● ● ADB ADC AAS AB = AC Congruent s Repeat for each side. End of Show AB = BC = AC