**Basic Geometrical Ideas**

**Question 1.Classify the following curves as**

**(i)**Open or

**(ii)**Closed.

**Solution:**

Open curves are (a) and (c) and closed curves are (b), (d) and (e).

**Question 2.Draw rough diagrams to illustrate the following:**

**(a)**Open curve

**(b)**Closed curve

**Solution:**Rough diagram to illustrate

**(a) Open curve is**

**(b) Closed curve is**

**Question 3.Draw any polygon and shade its interior.**

**Solution:**

We know that in a closed curve, the interior is inside of the curve. Thus, shaded portion of the polygon indicate its interior.

**Question 4.Consider the given figure and answer the questions:(a)** Is it a curve?

**(b)**Is it closed?

**Solution:(a)** Yes, the given figure represents a curve.

**(b)**Yes, the curve is closed.

**Question 5.Illustrate, if possible, each one of the following with a rough diagram:**

**(a)**A closed curve that is not a polygon.

**(b)**An open curve made up entirely of line segments.

**(c)**A polygon with two sides.

**Solution:(a)** Impossible, as a close plane figure bounded by lines is called a polygon.

**(b)** No, impossible, as a polygon of two sides cannot be drawn.

** (c) **Yes, it may be as