First step to solve a bearing problem involving trigonometry?
Draw a clear diagram with North lines at every point.
Write the Sine Rule for finding a side length.
sinAa=sinBb=sinCc
True or False?If calculating an angle using the Sine Rule, there is always only one possible answer.
FalseCorrect Answer: There could be two (Ambiguous Case).
When using the Cosine Rule to find an angle, which formula should you start with?
cosA=2bcb2+c2−a2
To find the angle in a triangle with sides 5, 6, and 7, which rule must you use?
Cosine Rule (SSS case).
When solving a triangle, if you know two sides and the included angle (SAS), which rule do you use first?
Cosine Rule
For the area formula Area=21absinC, what condition must angle C satisfy?
It must be the included angle between sides a and b.
When finding the area of a segment (shaded region cut by a chord), which two areas do you subtract?
Area of Sector - Area of Triangle
Write the conversion factor to change degrees to radians.
×180π
First step to solve 2θ+1.5=π for an angle in a circle sector problem?
Rearrange to find θ: θ=2π−1.5.
Which of these is 3 radians?1. Slightly less than 180∘2. Exactly 180∘3. Slightly more than 180∘
1. Slightly less than 180∘
To find the perimeter of a sector, what must you add to the arc length?
Two radii (2r).
Write the exact value of cos(3π).
21
True or False?An angle of 270∘ is equal to 32π radians.
FalseCorrect Answer: 23π radians
Write the formula for arc length l in a circle of radius r and angle θ radians.
l=rθ
True or False?The area of a sector with radius r and angle θ radians is A=πr2θ.
FalseCorrect Answer: A=21r2θ
Condition required to use the formula A=21r2(θ−sinθ)?
θ must be in radians.