Two geometric figures are congurent, if they are of the same shape and size.
AB =XY ∠a = ∠x
BC = YZ ∠b = ∠y
AC = XZ ∠c = ∠z
Tests of Congurency:
- Side Side Side (SSS) – all sides are equal
- Angle Angle Angle (AAA) – all angles are same
- Side Angle Side (SAS) – two sides and one angle are equal
- Right Angled – Hypotenuse – Side – one right angle and hyp & side equal
≡ – To denote “ is congruent to”
≢ – To denote “ is not congruent to”
When two figures are similar, they are exactl the same in shape but not in size.
- Equal corresponding Angles:
The angles of one triangle are equal to corresponding angles of the other triangle.
- Proportional Corresponding Angles.
- Two Pairs of Proportional Corresponding Sides with equal angles.
We right similarity as ( ~ ) i.e ΔABC ~ ΔDEF