Question

Identify closed curve

A. 1, 2
B. 1, 3
C. 2, 4
D. 3, 4

Answer 1

Hint:
> Closed shapes are the solid shapes which can be made of curves or straight lines
> Closed figures have all points connected with each other.

Complete step by step solution:
Closed figures have nothing open on any end. They have all sides connected with each other. The closed figures also do not have lines extending out of the shape.
There are different types of polygons which are closed in nature. For example- Triangle, square, pentagon, heptagon and etcetera are all closed shapes.

(1)

Shape ($1$) is a closed curve as all three lines of triangle in shape ($1$) are joined with each other.
(2)

Shape ($2$) is not a closed curve as one horizontal line at top is not connected with adjacent left vertical line. Shape ($2$) is an open curve.
(3)

Shape ($3$) is a closed curve as all the lines of triangle are joined to each other.
(4)

Shape ($4$) is not a closed curve as it is a spiral shape with no ends and thereby no corners. As there are no corners, there are open curves making shape ($4$) an open curve.

Out of all four shapes, shape ($1$) and ($3$) are closed curves which indicates option (B) is correct.

Note:
Closed figures can be $2$-D (two dimensional) or $3$-D (three dimensional) in nature.
Two dimensional figures have negligible width and can be drawn on paper only while three dimensional figures have width and are found in real life as various objects.