# Math Help - Easy Trigonometry Problem

1. ## Easy Trigonometry Problem

The angle formed by the diagonal of a rectangle and one of its shorter sides is 60°. If the diagonal is 8 cm long, find the dimensions of the rectangle, in surd form.

I am having trouble imagning this. I am also not sure what the question is asking me to do.

Any help regarding the problem above will be appreciated!

2. Hello,

Just apply the definition of cosine and sine in the right-angled triangle ABC :

$\cos 60=\frac{AC}{BC}$

$\sin 60=\frac{AB}{BC}$

and for the values of cos and sin, they're just common values.

3. Originally Posted by Moo
Hello,

Just apply the definition of cosine and sine in the right-angled triangle ABC :

$\cos 60=\frac{AC}{BC}$

$\sin 60=\frac{AB}{BC}$

and for the values of cos and sin, they're just common values.
Ok...thanks for the diagram. Now I know what I'm looking at! But I'm afraid I'm still a little lost.

4. Nevermind...I get it now!

EDIT:

See:

cos 60 = AC/BC
1/2 = x/8
8/2= x
x= 4

(√3)/2 = AB/BC
(√3)/2 = x/8
(8√3)/2 = x
x= 4√3

5. Originally Posted by Mr Rayon
Nevermind...I get it now!

EDIT:

See:

cos 60 = AC/BC
1/2 = x/8
8/2= x
x= 4

(√3)/2 = AB/BC
(√3)/2 = x/8
(8√3)/2 = x
x= 4√3
Yes

6. Originally Posted by Moo
Hello,

Just apply the definition of cosine and sine in the right-angled triangle ABC :

$\cos 60=\frac{AC}{BC}$

$\sin 60=\frac{AB}{BC}$

and for the values of cos and sin, they're just common values.
Hey, moo how'd you draw the right angle triangle? What software/file do you use? How can I do the same thing in a post in this forum?

7. Drew it in paint, then used the attachment option in a post to add it to my post.