Trigonometry 1

We use the trigonometric ratios when

• a right angled triangle we have two lengths and an angle

• a right angled triangle with two angles and a length

• a right angled triangle with two lengths to find the third

We use the Pythagoras theorem when...

• we have the length of two sides and need an angle

• we have a right angled triangle and the length of two sides and need the third

• we have any triangle with two lengths given and need the third

 $In\ a\ triangle\ ABC,\ angle\ A=x\degree,\ and\ angle\ B=2x\degree.\ What\ is\ the\ size\ of\ angle\ C?$  

•  $45\degree$  

•  $60\degree$  

•  $\left(\frac{180}{3x}\right)\degree$  

•  $\left(180-3x\right)\degree$  

 Find sinA

• 32/40
• 32/24
• 24/40
• 24/32

Given the point (3, 4), what is sine of the angle formed by the positive x-axis and the line connecting the point and the origin?

• 3/4

• 4/3

• 4/5

• 3/5

Given the point (3, 4), what is cosine of the angle formed by the positive x-axis and the line connecting the point and the origin?

• 3/4

• 5/4

• 3/5

• 4/5

What is the cosine of angle P?

• p/q
• q/r
• p/r
• r/q

Which method would you use to solve for x?

• Sine
• Cosine
• Tangent
• Pythagorean Theorem

Find tangent of θ.

• 8/12

• 23/12

• 8/23

• 12/23

Which trig function would you use with this diagram?

• ^Sin
• ^Cos
• ^Tan
• ^Wha??