Any drawing which is straight and non-straight drawn without lifting the pencil from the paper and without the use of a ruler is called a curve. In everyday use curve means ‘not straight’ but in mathematics, a curve can be straight line also.
Simple curve: – A curve that does not cross itself.
A closed curve has three parts which are as follows:
It refers to the inside or inner area of curve.
The yellow-coloured area is the interior of the figure.
It refers to the outside or outer area of curve.
The point marked B depicts the exterior of the curve.
It refers to the dividing line thus it divides the interior and exterior of the curve.
The black line which is dividing the interior and exterior of the curve of the boundary.