Shape and Space 10
1 mark · EasyState whether the sine rule or cosine rule would be used to find the third side of a triangle when you know two sides and the included angle.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
Cosine rule
Must show: 'Cosine rule' (accept 'cosine rule' or 'cosine law')
Also accept: Cosine law
Common mistakes: Sine rule
Show mark scheme and worked solution
Marking points
B1 · 1 mark · Writes 'cosine rule' or an accepted alternative.
Worked solution
Cosine rule is used when you know two sides and the included angle.