How many parts does a triangle have?
A) 2
B) 3
C) 6
D) 9

Hint:
Here, we have to use the concept of the lines and angles of geometry. The sides and angles are generally known as part of any shape. So by calculating the total number of sides and angles in a triangle will give us the total numbers of parts a triangle has.

Complete step by step solution:
Firstly draw a triangle ABC,

Now, as we can clearly see that there are three sides of the triangle i.e. AB, BC, AC and also we can clearly see that there are three angles in a triangle i.e. \[\angle {\rm{A, }}\angle {\rm{B, }}\angle {\rm{C}}\]
Therefore, the number of parts of a triangle is equal to the sum of the total number of sides and total number of angles of a triangle.
Number of parts of a triangle\[ = 3 + 3\]
Hence, a triangle has 6 parts.

So, option C is correct.

Note:
Geometry is the branch of mathematics that deals with points, lines and shapes.
There are some basic definitions which we need to know:
A triangle is a polygon with three edges/sides and three vertices. Side is one of the straight line segments which is used to construct/draw a polygon.
When two or more lines cross each other in a plane, they are called intersecting lines and the point where these lines intersect is called a Point of Intersection.
Properties of intersecting lines:
Two or more than two intersecting lines meet only at one point always.
The lines intersect each other at any angle. The angle that is formed is always greater than \[0^\circ \] and less than\[180^\circ \].
Vertically Opposite Angles (vertical angles) are the angles opposite each other when two lines intersect or cross each other and pairs of vertically opposite angles (vertical angles) are always equal to each other.