REVISION
Sine rule
The rule/rules
𝑎
𝑠𝑖𝑛 𝐴
𝑠𝑖𝑛 𝐴
𝑎
= 𝑠𝑖𝑛𝑏 𝐵 = 𝑠𝑖𝑛𝑐 𝐶
Or
𝑠𝑖𝑛 𝐵
𝑠𝑖𝑛 𝐶
=
=
𝑏
𝑐
When can I use What can I use it
it(What do I need for it for (What can I find
to work?)
with it?)
In any triangle with
matching pairs.
Eg. A & a, B & b,
C&c
To find missing sides
Or
To find missing angles
Cosine rule
1) a² = b² + c² - 2bc cos A
Or
2) Cos A = b² + c² - a²
2bc
Area of a
triangle
REVISION
Area = ½ab sin(C)
The rule/rules
1)When we are
given two sides and
the included angle
Or
2)If we have all
three sides.
1)To find the third
side.
When we are given
two sides and the
included angle
To find the area of a
Triangle
Or
2)To find any angle.
When can I use What can I use it
it(What do I need for it for (What can I find
to work?)
with it?)
Sine rule
𝑎
𝑠𝑖𝑛 𝐴
=
𝑏
𝑠𝑖𝑛 𝐵
=
𝑐
𝑠𝑖𝑛 𝐶
Or
𝑠𝑖𝑛 𝐴
𝑎
Cosine rule
=
𝑠𝑖𝑛 𝐵
𝑏
=
𝑠𝑖𝑛 𝐶
In any triangle with
matching pairs.
Eg. A & a, B & b,
C&c
Or
Or
To find missing angles
𝑐
3) a² = b² + c² - 2bc cos A
To find missing sides
1)When we are
given two sides and
the included angle
Or
2)If we have all
three sides.
1)To find the third
side.
When we are given
two sides and the
included angle
To find the area of a
Triangle
Or
2)To find any angle.
4) Cos A = b² + c² - a²
2bc
Area of a
triangle
Area = ½ab sin(C)
Area of a
sector of a
circle
Length of a Radius
and an angle (either
in degrees or in
radians)
To find the area of a
sector
Conversion of
degree/radia
n
An angle in degrees
or radians
Converting between
the two
Length of a Radius
and an angle (when
the angle is in
radians)
To find the length of
an arc.
Length of an
arc of a circle
S=rxθ