Further trigonometry - Higher
We are now going to extend trigonometry beyond right-angled triangles and use it to solve problems involving any triangle.
We can use the sine rule to find the size of an angle or length of a side.
The sine rule is:
We can use the sine rule when we are given:
Two sides and an angle opposite to one of the two sides.
One side and any two angles.
Find the size of angle R.
R = 25.4°
Using the sine we can write:
Multiplying both sides by 4, we get
SO R = inv sin(0.4293)
R = 25.4° (1dp)
Remember: Use the formula which has the unknown at the top of the fraction.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.