Geometry - Ch. 3: Proofs (8 of 17) Properties of Congruences Needed for Proofs

In this video I will list and explain 4 properties of congruence needed (applied to line segments, angles and right angles.

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[ievgen]

It's a little unclear why the measure of vertical angles is 90. They are equal, but their measure depends on the second pair (to make 360 together). Right?

Thank you for your work, it helps a lot.