Topic/Skill
Topic: Definition/Tips
Right Angled Trigonometry Example
1. The study of triangles.
Trigonometry
2. Hypotenuse The longest side of a right-angled
triangle.
Is always opposite the right angle.
3. Adjacent Next to
4. Use SOHCAHTOA.
Trigonometric
Formulae O
sin θ=
H
A
cos θ=
H Use ‘Opposite’ and ‘Adjacent’, so use
‘tan’
O x
tanθ= tan 35=¿ ¿
A 11
x=11 tan 35=7.70 cm
When finding a missing angle, use the
‘inverse’ trigonometric function by
pressing the ‘shift’ button on the calculator.
Use ‘Adjacent’ and ‘Hypotenuse’, so
use ‘cos’
5
cos x=
7
x=cos−1 ( 57 )=44.4 °
5. 3D Find missing lengths by identifying right
Trigonometry angled triangles.
You will often have to find a missing
length you are not asked for before finding
the missing length you are asked for.
Mr A. Coleman Glyn School
Topic: Definition/Tips
Right Angled Trigonometry Example
1. The study of triangles.
Trigonometry
2. Hypotenuse The longest side of a right-angled
triangle.
Is always opposite the right angle.
3. Adjacent Next to
4. Use SOHCAHTOA.
Trigonometric
Formulae O
sin θ=
H
A
cos θ=
H Use ‘Opposite’ and ‘Adjacent’, so use
‘tan’
O x
tanθ= tan 35=¿ ¿
A 11
x=11 tan 35=7.70 cm
When finding a missing angle, use the
‘inverse’ trigonometric function by
pressing the ‘shift’ button on the calculator.
Use ‘Adjacent’ and ‘Hypotenuse’, so
use ‘cos’
5
cos x=
7
x=cos−1 ( 57 )=44.4 °
5. 3D Find missing lengths by identifying right
Trigonometry angled triangles.
You will often have to find a missing
length you are not asked for before finding
the missing length you are asked for.
Mr A. Coleman Glyn School
