Isosceles triangle
An isosceles triangle is a triangle with two sides of equal length.
The two equal sides are called the legs and the third side is called the base. The angles at the base are called the base angles, and the angle opposite the base is called the vertex angle.
Types of isosceles triangles: Isosceles acute triangle: Acute isosceles triangle. This triangle has two acute angles and one obtuse angle. The acute angles are congruent and the obtuse angle is formed by the two equal sides. Isosceles right triangle: Isosceles right triangle. This triangle has a right angle, an acute angle of 45° and another acute angle of 45°. Isosceles obtuse triangle: Isosceles obtuse triangle. This triangle has one obtuse angle, two congruent acute angles.
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