Basic Geometrical Ideas
Question 1.
Use the figure to name:
(a) Five points
(b) A line
(c) Four rays
(d) Five line segments
Solution:
Clearly, from the given figure
(a) 5 points are points, O, C, B, D and E.
(b) A line is [altex]\overleftrightarrow { BD } [/latex]
(c) 4 rays are and
.
(d) 5 line segments are and
.
Question 2.
Name the line given in all possible (twelve) ways, choosing only two letters at a time from the four given.
Solution:
All the possible ways of naming the given by choosing only two letters at a time out of 4 letters are and
.
Question 3.
Use the figure to name :
(a) Line containing point E.
(b) Line passing through A.
(c) Line on which O lies.
(d) Two pairs of intersecting lines.
Solution:
Clearly, from the given figure
(a) Line containing pqint E is .
(b) Line passing through A is .
(c) O lies on the line .
(d) Two pairs of intersecting lines are and
.
Question 4.
How many lines can pass through
(a) one given point?
(b) two given points?
Solution:
(a) An unlimited number of lines can be drawn passing through a given point.
(b) Exactly one line can be drawn passing through two different given points in a plane.
Question 5.
Draw a rough figure and label suitably in each of the following cases:
(a) Point P lies on .
(b) and
intersect at M.
(c) Line l contains E and F but not D.
(d) and
meet at O.
Solution:
A rough figure and labelled suitably for the given cases are as under:
(a) Point P lies on :
(b) and
intersect at M:
(c) Line l contains E and F but not D:
(d) and
meet at O.
Question 6.
Consider the following figure of line MN. Say whether following statements are true or false in context of the given figure.
(a) Q, M, O, N, P are points on the line .
(b) M, O, N are points on a line segment .
(c) M and N are end points of line segment .
(d) O and N are end points of line segment .
(e) M is one of the end points of line segment .
(f) M is point on ray .
(g) Ray is different from ray
.
(h) Ray is same as ray
.
(i) Ray is not opposite to ray
.
(j) O is not an initial point of .
(k) N is the initial point of and
.
Solution:
In the context of the given figure, the given statement is:
(a) True
(b) True
(c) True
(d) False
(e) False
(f) False
(g) True
(h) False
(i) True
(j) False
(k) True