(i) Opposite edges of a scale
(ii) Opposite edges of a blackboard
(iii) Opposite edges of an envelope
(iv) Opposite edges of a rectangle
(v) Opposite edges of a page of any book
(vi) Rail lines on a railway track
(vii) Opposite edges of a file
(viii) Opposite edges of a carbon paper
(ix) Opposite edges of a rhombus
(x) Opposite edges of a page of a newspaper

(a) The points, which are in the exterior are F, G and H.
(b) Interior points are A,O and C.
(c) The points, which lie on the circle are B, D and E.

Parallel lines in the above figures are
(i) ST and QR.
(ii) PQ and SR, SP and QR.
(iii) PQ and SR, QR and SP.
(iv) PQ and TS, QR and TN, SR and NP.

In the given figures (i) and (ii), both have three line segments. Figure (i) is not a triangle, because it is not a closed curve.

The vertices of the figure are A. B, C,D, E and the line segments are \(\bar {AB},\bar {BC},\bar {CD},\bar {DE},\bar {EA},\bar {AC},\bar {AD}\).

Zero

(i) A triangle is a three sided polygon. A rough sketch of a \(\triangle ABC\) is given.
(ii) From the figure, point P is inside the \(\triangle ABC\) and point Q is outside the \(\triangle ABC\). The point A is neither in the exterior nor in the interior of \(\triangle ABC\) because point A is the vertex of \(\triangle ABC\) ,so it lies on the \(\triangle ABC\).

\(\angle CAB,\angle ACB,\angle CBA,\ or \angle A,\angle B,\angle C\)

ABCD is a polygon, where interior is shaded as given below:

The curve given below is a closed curve, since its ends are joined:

(i) Vertices of given polygon are A, B, C and D.

(ii) Sides are AB, BC, CD and AD.
(iii) Diagonals are AC and BD.

We know that, a line is a line segment which can extend indefinitely in both directions. Name oflines in all possible ways are as follow:
(i) By taking A, all possible ways are \(\overleftrightarrow { AB } ,\overleftrightarrow { AC } and\overleftrightarrow { AD } \).
(ii) By taking B, all possible ways are \(\overleftrightarrow { BC } ,\overleftrightarrow { BD } and\overleftrightarrow {BA } \).
(iii) By taking C, all possible ways are \(\overleftrightarrow { CD } ,\overleftrightarrow { CA } and\overleftrightarrow {CB } \).
(iv) By taking D, all possible ways are \(\overleftrightarrow { DA } ,\overleftrightarrow { DB } and\overleftrightarrow {DC } \).

We know that, a ray is a part of a line which starts at one point and goes endlessly in a direction.
(a) In the given figure, there are four rays namely \(\vec {TA}\), \(\vec {TN}\), \(\vec {NB}\) and \(\vec {TB}\).
(b) No, T is not a starting point of each of these rays. T is a starting point of \(\vec {TA}\), \(\vec {TB}\) and \(\vec {TN}\) only but not of \(\vec {NB}\).