Transcript LHT_Trigonometry

Mathematics
GCSE Topic Reminders
Learning how to …
use trigonometry to find an
angle in a right angled
triangle.
We already know how to …
label the sides …
Opposite the
right angle
Opposite
Hypotenuse
x
Opposite the
angle we need
Adjacent
Next to the
angle we need
We already know …
Opposite
The formula for SINE …
Hypotenuse
x
Adjacent
Sin x
=
Opposite
Hypotenuse
We already know …
Opposite
The formula for COSINE …
Hypotenuse
x
Adjacent
Cos x
=
Adjacent
Hypotenuse
We already know …
Opposite
The formula for TANGENT
Hypotenuse
x
Adjacent
Tan x
=
Opposite
Adjacent
…
Don’t
use a
protractor
Label the given sides in relation to
the angle you need to find
Adjacent
Opposite
Hypotenuse
Choose SIN, COS or TAN depending
on the sides given
Adjacent
Opposite
‘Opposite’ &
‘Adjacent’ means we’ll
be using TAN for this
question
Write out the formula with
correct numbers
Adjacent
Opposite
Tan x =
138
177
opposite
adjacent
GCSE 1st
Key 2nd (or INV ) TAN 138  177 =
into the calculator to give the angle x
Adjacent
Opposite
Calculator
set to DEG
Tan x =
x = 37.9o
138
177
GCSE 2nd & 3rd