Geometry is the next we shall be considering in this chapter, under Pure Mathematics.
Geometry has to do with fundamental concepts like Points, Lines, and Angles, along with Shapes such as Polygons (and Triangle, which is the simplest type of polygon) and Circles.
1. TRIGONOMETRY (TRIANGLES)
Triangle is the first we want to seriously consider under Geometry.
A Triangle, as the name implies, is a polygon having 3 straight Lines (or Sides) and 3 Angles.
The 3 lines could be equal or unequal; the angles could be equal or unequal as well. Which is why we have different types of Triangles. A Triangle name is dependent on its lines and angles.
But below are the general things about all types of Triangles:
i. Every triangle has 3 sides;
ii. Every triangle has 3 angles;
iii. The Sum of the 3 angles in any triangle (A,B,C) is 180 degrees.
iv. An external angle of a triangle is equal to the sum of the 2 internal opposite angles.
TYPES OF TRIANGLES:
Triangle types are categorized based on two things, Sides and Angles.
Based on Sides, we have
*EQUILATERAL TRIANGLE,
*ISOSCELES TRIANGLE and
*SCALENE TRIANGLE.
And based on Angles, we have
*RIGHT-ANGLED TRIANGLE,
*ACUTE-ANGLE TRIANGLE and
*OBTUSE-ANGLE TRIANGLE.