How do I know which out of the Sine and Cosine rule I should use?

If you look at the formulae for the Sine and Cosine rules you'll see that the Sine rule involves two angles and two sides and the Cosine rule involves one angle and three sides.So have a look at the problem you're given and see how many angles and sides you are given and which ones you're trying to work out:-if you're given: a) two sides and an angle (you're trying to work out the second angle) or b) two angles and a side (you're trying to work out a second side) then use the Sine rule.-if you're given: a) three sides (you're trying to work out an angle) or b) two sides and an angle (yo're trying to work out the third side) then it's the Cosine rule.

Answered by Julian H. Maths tutor

4581 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Solve the simultaneous equations: 2x + y = 18 and x - y = 6


N = 2a + b. a is a 2 digit square number, b is a 2 digit cube number. What is the smallest possible value of N?


Give the possible values of x when 2x^2-x-6=0


Factorise and solve x^2 -8x=15=0


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences