Khan Academy

Area of trapezoid on the coordinate plane (K-A)

Challenge problem: Points on two circles (K-A)

Coordinate plane word problem (K-A)

Points inside/outside/on a circle (K-A)

Parallel & perpendicular lines from graph (K-A)

Parallel & perpendicular lines intro (K-A)

Parallel lines from equation (example 2) (K-A)

Parallel lines from equation (example 3) (K-A)

Parallel lines from equation (K-A)

Perpendicular lines from equation (K-A)

Proof: parallel lines have the same slope (K-A)

Proof: perpendicular lines have negative reciprocal slope (K-A)

Writing equations of perpendicular lines (example 2) (K-A)

Writing equations of perpendicular lines (K-A)

Classifying quadrilaterals on the coordinate plane (K-A)

Congruent shapes & transformations (K-A)

Non-congruent shapes & transformations (K-A)

Congruent triangles & the SSS postulate/criterion (K-A)

Determining congruent triangles (K-A)

Triangle congruence postulates/criteria (K-A)

Triangle congruence review (K-A)

Why SSA isn't a congruence postulate/criterion (K-A)

Angles in a triangle sum to 180° proof (K-A)

Proofs concerning equilateral triangles (K-A)

Proofs concerning isosceles triangles (K-A)