ೃ⁀➷ 𝐄𝐦𝐚𝐭𝐡: 𝐓𝐫𝐢𝐚𝐧𝐠𝐥𝐞𝐬

Triangle

A plane closed figure formed by three line segments, having three angles and three sides.

Vertices

The angles in a triangle; plural for vertex.

Exterior Angle

The angle formed with one side and the adjacent extended side of a triangle; the sum of the exterior angles of a triangle is always 360°.

Right Triangle

A triangle in which one angle is a right angle; the two sides forming the right angle are called legs, and the opposite side is called the hypotenuse.

Legs

The two sides that form the right angle in a right triangle.

Hypotenuse

The side opposite the right angle in a right triangle.

Pythagorean Theorem

A theorem stating that the square of the hypotenuse in a right triangle is equal to the sum of the squares of the two legs.

30°-60°-90° Triangle

A right triangle whose acute angles measure 30° and 60°.

Isosceles Right Triangle

A triangle with two equal sides (legs), a right angle, and two congruent acute angles.

Equilateral Triangle

A triangle with all sides equal in length; each angle measures 60°.

Altitude

The perpendicular line segment connecting a vertex of the triangle to the line containing the opposite side.

Scalene Triangle

A triangle with no two equal sides.

Isosceles Triangle

A triangle with two sides of the same length.

Acute Triangle

A triangle with all angles less than 90°.

Right Triangle

A triangle with one angle measuring 90��.

Obtuse Triangle

A triangle with one angle measuring more than 90°.

Equiangular Triangle

A triangle with all angles equal.

Base

The side opposite the vertex in a triangle.