Prove theorems about triangles. Theorems include: measures of interior angles of a triangle sum to 180°; base angles of isosceles triangles are congruent; the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length; the medians of a triangle meet at a point.
Isosceles triangle angles - Median Don Steward Angles practice makes perfect - Median Don Steward Angle facts questions ( answers & supporting material ) - @taylorda01
Isosceles triangles are very helpful in determining unknown angles. In an isosceles triangle, the two equal sides are called legs, and the remaining side is called the base. The angle opposite the base is called the vertex angle, and the point associated with that angle …
Because the Right Isosceles is formed from the square, we know that two of the sides must congruent and that the base angles must be equal (45°each). Let us now look at the side relationships. These examples help us to see a pattern with the three sides of a RIGHT ISOSCELES (45°, 45°, 90°) triangle.