# Trigonometry Quiz

## The questions are based on the figure below: 1.) The area of the triangle is given by ...

A   $A = ½ (a+b)c$
B   $A = ½ a · b$
C   $A = ½ a · c$
D   $A = a2 + b2 - c2$

2.) Which expression is wrong:

A   $c2 = a2 + b2$
B   $c2 - a2 = b2$
C   $b2 - c2 = a2$
D   $b2 - a2 + 2a2 = c2$

3.) Which expression regarding the values of the angles is right:

A   $α + β < 90^\circ$
B   $α + β > 90^\circ$
C   $180^\circ + (α + β) = 360^\circ$
D   $180^\circ - α = 90^\circ + β$

4.) If the length of side c is 13 cm, the length of side a is 5 cm, what will be the length of side b?

A   7 cm
B   8 cm
C   12 cm
D   18 cm

5.) Which expression is correct?

A   $\sin β = c/b$
B   $\sin β = b/a$
C   $\sin α = b/c$
D   $\sin α = a/c$

6.) Spot the mistake:

A   $\sin β = b/a$
B   $\sin α = a/c$
C   $\cos β = a/c$
D   $\cos α = b/c$

7.) Identify the wrong expression:

A   $a = c · \sin α$
B   $a = c · \cos α$
C   $b = c · \sin β$
D   $a = c · \cos β$

8.) The tan of angle $β$ is given by ...

A   $\tan β = b/a$
B   $\tan β = a/b$
C   $\tan β = b/c$
D   $\tan β = a/c$

9.) The sin of $30^\circ$ is ...

A   1
B   2/3
C   1/2
D   1/4

10.) The cos of $60^\circ$ is the same as ...

A   $\tan 45^\circ$
B   $\tan 60^\circ$
C   $\sin 30^\circ$
D   $\sin 60^\circ$