Page 134 - Math Smart - 7

5 Find the 168° mark on the outer scale of the
protractor. Mark a point and label it as R.

Remove the protractor. Draw a straight line to
join point R to point Q. The angle (^PQR) is
168°.

Drawing reflex angles

Draw an angle aPOR = 295°.
To draw a reflex angle:

1
Use your ruler. Draw a straight line OP.
This forms one arm of the angle.

Mark point O as the vertex. Extend the line
0
from the vertex to form a straight line (180®).

295' 180'
Calculate the extra angle that is needed. For
example, to draw an angle of 295®, you need ,115'
180® + 115°.

295°
Place the protractor on line OP. Align the
centre mark of the protractor with point O
the vertex. Make sure the baseline of the
protractor is sitting on line OP. Find the 115^
mark on the outer scale of the protractor.
Mark the point. The angle (^POR) is 295°.

Check My
Understanding

9 Use your ruler and protractor to draw the following angles,

a) 30® b)47® c) 109® d) 98® e) 67® f) 151' g) 147® h) 126®
Q Use your ruler and protractor to draw the following reflex angles.

a) 190° b)209® c) 236® d) 317® e) 342® f) 359® 9) 333® h) 227®

Angles and Their Properties