Junior Certificate Geometry Applets Click on the links below to open the appropriate Junior Certificate Geometry applet. All applets open in a new window. Note that the official titles of some of the longer Theorems/Facts have been shorten so that they will fit on the screen. Number Theorem/Fact 1 A Straight Angle Measures 180 Degrees 2 Theorem 1 - Vertically Opposite Angles are Equal in Measure 3 Alternate Angles are Equal in Measure 4 Corresponding Angles are Equal in Measure 5 Theorem 2 - The Sum of the Three Angles in a Triangle is 180 degrees 6 Theorem 3 - The Exterior Angle in a Triangle 7 Congruent Triangles - Three Sides (SSS) 8 Congruent Triangles - Two Sides and including Angle (SAS) 9 Congruent Triangles - Two Angles and the Corresponding Side (ASA) 10 Congruent Triangles - A Right Angle, Hypotenuse and a Side (RHS) 11 Theorem 4 - Isosceles Triangle 12 Theorem 4 Converse - Isosceles Triangle 13 Triangle with Two Sides Unequal in Length 14 Any Two Sides of a Triangle are Greater than the Third 15 Rectilinear Figure 16 Theorem 5 - Opposite Angles and Sides of a Parallelogram 17 Theorem 6 - A Diagonal Bisects the Area of a Parallelogram 18 Theorem 7 - The Diagonals of a Parallelogram Bisect each other 19 Area of a Rectangle = Length x Breadth 20 Theorem 8 - The Area of a Triangle 21 Theorem 9 - The Area of a Parallelogram 22 Theorem 10 - Points on the Perpendicular Bisector of a Line Segment 23 Theorem 10 Converse 24 Theorem 11 - Angle Bisector 25 Theorem 12 - Angle at the Centre of a Circle 26 Theorem 12 Deduction 1 27 Theorem 12 Deduction 2 28 Theorem 12 Deduction 3 29 Theorem 13 - Tangent Perpendicular to Diameter of a Circle 30 Theorem 14 - Perpendicular to Chord from Centre of Circle Bisects the Chord 31 Theorem 15 - Division of Sides of a Triangle in Equal Ratios 32 Theorem 15 Deduction 33 Theorem 16 - Similar Triangles 34 Theorem 17 - Theorem of Pythagoras
