Page 15 - Key Stage 3 Geometry

Can you identify which ones are acute, obtuse and

reflex angles?

o
Once you reach 360 you will have completed a whole
circle. When you combine all 12 sectors you get,

Each sector has an angle of
o
30 . When you look closely at
your protractor you may think
o
an angle of 1 is small and as
mentioned each of these is

divided into 60 minutes and
each minute is divided in 60

arcseconds – which appears to be a pretty small angle.
However, when performing measurements in

astronomy, the arcsecond is quite

common. When you look up into
the night sky to observe the

planet Jupiter the angle formed

between its equatorial axis and
your eye is about 33 arcseconds.

When you are looking at the

moon which is much closer, the
angle subtended by its equatorial

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