The base angles of an isosceles triangle are congruent. The vertex angle of an isosceles triangle is not necessarily congruent to the base angles.
Vertex angle
-- An isosceles triangle has two equal sides. -- An isosceles triangle has two equal angles. -- An isosceles triangle has two equal interior-angle bisectors. -- The bisector of the vertex angle of an isosceles triangle is also the perpendicular bisector of the triangle's base.
The base
The two "base" angles.
The base angles of an isosceles triangle are congruent. The vertex angle of an isosceles triangle is not necessarily congruent to the base angles.
The third angle of an isosceles triangle doesn't have a name.
Vertex angle
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-- An isosceles triangle has two equal sides. -- An isosceles triangle has two equal angles. -- An isosceles triangle has two equal interior-angle bisectors. -- The bisector of the vertex angle of an isosceles triangle is also the perpendicular bisector of the triangle's base.
No. It need not be the base angles that are equal, it can be one of the base angles and the top angle (if the triangle is tipped over). Also, the base angle are equal in an equilateral triangle - although an equilateral triangle is a special kind of isosceles triangle.
The base
The two "base" angles.
No, an obtuse triangle cannot be isosceles. An isosceles triangle has two sides that are equal in length, but in an obtuse triangle, the angles are all greater than 90 degrees. Therefore, the sides cannot be equal in length.
No the 2 equal base angles cannot be obtuse because the 3 interior angles of any triangle add up to 180 degrees
For an isosceles triangle with vertex 46 degrees, the sum of the remaining two base angles is 180-46 = 134 degrees. Base angles are equal because it's isosceles, so each angle is half of their sum. 134/2 = 67 degrees. Thus, any isosceles trapezoid formed inside that isosceles triangle by drawing parallel lines to the triangle's base, will have base angle measures of 67 degrees, which are triangle's base angles.
The base angles of an isosceles triangle are the two angles that are equal to each other. They can be between 89.999...o and 0.000000..01o.