7ULJRQRPHWU\3URRIV
[
F
D
\
E
Fill in the blanks in the following fractions with D, E, F :
sin [ =
cos [ =
sin \ =
cos \ =
The expressions above are in two equal pairs. Write which ones are equal
below:
sin [ =
cos [ =
Now use what you know about the sum of angles in a triangle to write
\ in terms of [ :
\=
Finally substitute this expression for
sin [ =
\
into the above expressions:
cos [ =
7ULJRQRPHWU\3URRIV
[
F
D
\
E
Fill in the blanks in the following fractions with D, E, F :
sin [ =
cos [ =
Now divide your expression for
and cancel:
sin [
tan [ =
by your expression for
cos [
sin [
=
cos [
The answer that you get should be the same as one of your original
expressions. Rewrite in terms of this:
sin [
=
cos [
7ULJRQRPHWU\3URRIV
[
F
D
\
E
Fill in the blanks in the following fractions with D, E, F :
sin [ =
cos [ =
Rearrange the above equations to get an expression for
expression for E :
D=
D
and an
E=
Use Pythagoras Theorem to write an equation linking
Now substitute your expressions for
equation:
D
and
D , E, F :
E into your Pythagoras
Simplify and divide your equation through by
F2 :