Page 181 - ICSE Math 6

P
Step 2: With C as centre and radius more than half of CD, draw Q
an arc. With the same radius and D as centre, draw another
arc intersecting the previous arc at Q. A C D B

P
Q
Step 3: Join P and Q and extend it to intersect line AB at O. C O D
Thus, PO is the required perpendicular to line AB. A B

From a point on the line

Let AB is a line and P is a point on it.
To draw a perpendicular to line AB from point P, follow the steps A P B
given below.
A C P D B
Step 1: With P as centre, draw an arc of suitable radius to intersect
line AB at C and D.

Q

Step 2: With C as centre and radius more than half of CD, draw
an arc. With the same radius and D as centre, draw another A C P D B
arc intersecting the previous arc at Q.

Q
Step 3: Join P and Q. Thus, PQ is the required perpendicular to
line AB. A C P D B

EXERCISE

1. Construct angles equal to the given angles using a ruler and a compass.

A
A A
(a) (b) (c)

B B
C C C B
2. Using a protractor, draw the following angles.
(a) 72° (b) 36° (c) 156° (d) 135° (e) 90°

3. Using a ruler and a compass, construct the following angles and then bisect them.
(a) 30° (b) 60° (c) 90° (d) 120° (e) 135°
4. Draw a line segment AB of length 6 cm and then draw its perpendicular bisector PQ intersecting
AB at O. Is AO = BO?

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