Basic Concepts in Geometry
- Concept of Triangles - Sides, Angles, Vertices, Interior and Exterior of Triangle
- Theorem of remote interior angles of a triangle
- Congruence of Triangles
- Isoscles Triangle Theorem
- Property of 30-60-90 Triangle Theorem
- Median of a Triangle
- Perpendicular bisector Theorem
- Angle bisector theorem
- Properties of inequalities of sides and angles of a triangle
- Similar Triangles
Constructions of Triangles
Surface area and volume
- Remote-Interior Angles of a Triangle Theorem
- Property of an exterior angle of triangle
In the given figure, ∠ ACD is an exterior angle of Δ ABC . ∠ B = 40°, ∠ A = 70°.
Find the measure of ∠ ACD.
The measure of one of the angles of a triangle is twice the measure of its smallest angle and the measure of the other is thrice the measure of the smallest angle. Find the measures of the three angles.
In the given figure, measures of some angles are given. Using the measures find the values of x, y, z.
In the given figure, line AB || line DE. Find the measures of ∠ DRE and ∠ ARE using given measures of some angles.
In the given Figure, line AB || line CD and line PQ is the transversal. Ray PT and ray QT are bisectors of ∠ BPQ and ∠ PQD respectively.
Prove that m ∠ PTQ = 90 °.
In the given figure, line DE || line GF ray EG and ray FG are bisectors of ∠ DEF and ∠ DFM respectively. Prove that,
1. `angle DEG = 1/2 angle EDF`
2. EF = FG