Geometry Lessons for Grade 10
Prove congruence and similarity, investigate triangle centers and circle theorems, and use right-triangle trigonometry to calculate missing measures. These lessons give each idea room for an interactive diagram, worked examples, and hands-on exploration.
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Postulates & Axioms
Postulates and axioms are accepted rules such as the ruler postulate and segment addition.
Open lesson →Skew Lines
Skew lines lie in different planes, are not parallel, and never meet.
Open lesson →Centroid
The centroid is the point where the medians intersect.
Open lesson →Incenter
The incenter is the point where the angle bisectors intersect.
Open lesson →Circumcenter
The circumcenter is the point where the perpendicular bisectors intersect.
Open lesson →Orthocenter
The orthocenter is the point where the altitudes intersect.
Open lesson →Segment
A circle segment is the region between a chord and its arc.
Open lesson →Annulus
An annulus is the ring-shaped region between two concentric circles.
Open lesson →Inscribed Angle
An inscribed angle has its vertex on the circle and intercepts an arc.
Open lesson →Tangent-Chord Angle
A tangent-chord angle is formed by a tangent and a chord through the point of tangency.
Open lesson →Circle
A circle is a conic section consisting of all points a fixed distance from one center.
Open lesson →Platonic Solids
Platonic solids are regular polyhedra with congruent faces and identical vertices.
Open lesson →Geometric Mean
The geometric mean can relate segments in right triangles and proportional figures.
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