Intermediate Geometry

Intermediate Geometry explores the properties and relationships of shapes, sizes, and theorems in two and three dimensions.

Basic Concepts

Properties of Triangles

Understanding Triangles

Triangles are the most basic polygon with three straight sides and three angles. Each triangle's internal angles add up to \(180^\circ\), a rule known as the Triangle Angle Sum Theorem.

Types of Triangles

  • Equilateral Triangle: All sides and angles are equal.
  • Isosceles Triangle: Two sides (and two angles) are equal.
  • Scalene Triangle: All sides and angles are different.
  • Right Triangle: Contains one \(90^\circ\) angle.

Special Properties

The Pythagorean Theorem applies to right triangles and states that: \[ a^2 + b^2 = c^2 \] where \(a\) and \(b\) are the legs and \(c\) is the hypotenuse.

Triangles are used in many fields, such as engineering (truss bridges) and art (design patterns).

Real-World Connections

Triangles provide structural stability and are found in roof supports, bridges, and sculptures.

Key Formula

\[a^2 + b^2 = c^2\]

Examples

  • A triangle with sides 3, 4, and 5 units is a right triangle because \(3^2 + 4^2 = 5^2\).

  • Roof trusses use equilateral triangles for strength and balance.

In a Nutshell

Triangles have unique side and angle properties, with applications in design and engineering.

Key Terms

Triangle
A polygon with three straight sides and three angles.
Hypotenuse
The longest side of a right triangle, opposite the right angle.