Page 56 - Year 9

Arcs and Sectors Maths set 1 and 2 Maths: 5 of 7

Parts of a Radius – the distance from the centre of
Circle a circle to the edge

Diameter – the total distance across
the width of a circle through the centre.

Circumference – the total distance
around the outside of a circle

Chord – a straight line whose end points
lie on a circle

Tangent – a straight line which touches
a circle at exactly one point

Arc – a part of the circumference of a What is the length of the…
circle
Circumference :________
Sector – the region of a circle enclosed
by two radii and their intercepted arc Diameter :________

Segment – the region bounded by a Arc :________
chord and the arc created by the
chord Radius :________
Circumference = which means ‘pi x diameter’ Arc Length The arc length is part of the Arc Length =
of a Circle of a Sector circumference.
If the radius was 5cm, then: 115
× × 8 = 8.03
360
= × 10 = 31.4

Area of a = which means ‘pi x radius Area of a The area of a Area =

Circle squared’. Sector sector is part
of the total area. 115 2 2
If the radius was 5cm, then: × × 4 = 16.1
360
2 2
= × 5 = 78.5