Triangles

What is a Triangle:

A polygon with 3 edges,
3 vertices, 3 angles.

We take 3 points and connect them with 3 sides below denoted as ΔPQR:

Properties of a Triangle:

Sum of the three interior angles = 180°
Sum of the 2 sides > 3rd side
A triangle with vertices (points) P, Q, R:
is denoted as ΔPQR

Area of a Triangle

With base b and height h:
A = 1/2bh

Acute Triangle:

All 3 angles measure less than 90°

Right Triangle:

Has one angle measuring 90° (right)
The other two angles < 90°

Obtuse Triangle:

Has only one angle measuring > 90°
Obtuse angle is opposite the long side

Scalene Triangle

No Sides Are Equal

Isosceles Triangle

2 sides Are Equal

Equilateral Triangle

All 3 sides are equal