Flashcards · Maths · Further Trigonometry
The Sine Rule
-
What is the sine rule for finding a side?
\(\dfrac{a}{\sin A} = \dfrac{b}{\sin B}\).
-
What is the sine rule for finding an angle?
\(\dfrac{\sin A}{a} = \dfrac{\sin B}{b}\).
-
What is a matching pair?
A side and its opposite angle.
-
Which side is opposite angle \(C\)?
Side \(c\).
-
When do you use the sine rule?
When you have a matching pair and one other side or angle.
-
When do you use the cosine rule instead?
With two sides and the included angle, or three sides.
-
What is \(\sin 30^\circ\)?
\(\dfrac{1}{2}\).
-
What is \(\sin 45^\circ\)?
\(\dfrac{\sqrt{2}}{2}\).
-
What is \(\sin 60^\circ\)?
\(\dfrac{\sqrt{3}}{2}\).
-
Which angle is opposite the longest side?
The largest angle.
-
What do the angles in a triangle add up to?
\(180^\circ\).
-
If two angles are \(30^\circ\) and \(45^\circ\), what is the third?
\(105^\circ\).
-
What does the sine rule say about the ratio of side to sine?
It is the same for all three sides.
-
How do you rearrange to make \(b\) the subject?
\(b = \dfrac{a \sin B}{\sin A}\).
-
Should you label the triangle first?
Yes, write the letters on a sketch.
-
What should you write before rearranging?
The sine rule with the numbers in.