Respuesta :
As isosceles triangle has two congruent sides with a third side
that is the base.
A base angle of an isosceles triangle is one of the angles formed by
the base and another side. Base angles are equal because of the
definition of an isosceles triangle.
A picture would probably help here:
A
.
/ \ ABC = ACB = 39 degrees
/ BAC = ??
._______________.
B C
base
ABC is the isosceles triangle. AB is congruent to AC. Angle ABC
is congruent to angle ACB. These are the base angles.
Triangle is a convex polygon with three segments joining three non-collinear points. Each of the three segments is called a side, and each of the three non-collinear points is called a vertex.
Triangles can be categorized by the number of congruent sides they have. For instance, a triangle with no congruent sides is a scalene triangle; a triangle with two congruent sides is an isosceles triangle; a triangle with three congruent sides is an equilateral triangle.
Triangles can also be categorized by their angles. For instance, a triangle with three acute interior angles is an acute triangle; a triangle with one obtuse interior angle is an obtuse triangle; a triangle with one right interior angle is a right triangle; a triangle with three congruent interior angles is an equiangular triangle.
One property of a triangle is that the sum of the measures of the three interior angles is always 180 degrees (or pi radians). In addition, the exterior angle of a triangle is the supplement of the adjacent interior angle. The measure of the exterior angle is also the sum of the measures of the two remote interior angles.
that is the base.
A base angle of an isosceles triangle is one of the angles formed by
the base and another side. Base angles are equal because of the
definition of an isosceles triangle.
A picture would probably help here:
A
.
/ \ ABC = ACB = 39 degrees
/ BAC = ??
._______________.
B C
base
ABC is the isosceles triangle. AB is congruent to AC. Angle ABC
is congruent to angle ACB. These are the base angles.
Triangle is a convex polygon with three segments joining three non-collinear points. Each of the three segments is called a side, and each of the three non-collinear points is called a vertex.
Triangles can be categorized by the number of congruent sides they have. For instance, a triangle with no congruent sides is a scalene triangle; a triangle with two congruent sides is an isosceles triangle; a triangle with three congruent sides is an equilateral triangle.
Triangles can also be categorized by their angles. For instance, a triangle with three acute interior angles is an acute triangle; a triangle with one obtuse interior angle is an obtuse triangle; a triangle with one right interior angle is a right triangle; a triangle with three congruent interior angles is an equiangular triangle.
One property of a triangle is that the sum of the measures of the three interior angles is always 180 degrees (or pi radians). In addition, the exterior angle of a triangle is the supplement of the adjacent interior angle. The measure of the exterior angle is also the sum of the measures of the two remote interior angles.
Answer:
An exterior angle of a triangle equals 180° minus the adjacent interior angle.
Step-by-step explanation:
The two angles are said to be adjacent if they have a common vertex and a common side between them.
So, if an angle is exterior to any angle of a triangle, But that particular angle of a triangle is adjacent to the exterior angle. Then, The both angles must lie on the straight line and thus both will form a linear pair.
The measure of the linear pair is always supplementary.
⇒ Exterior angle + Adjacent interior angle = 180°
⇒ Exterior angle = 180° - Adjacent interior angle
Hence, An exterior angle of a triangle equals 180° minus the adjacent interior angle.
