In triangle ABCABCABC, side AB AB\,AB has length 9 cm, side BC BC\,BC has length 5 cm and the cosine of angle ACB ACB\,ACB is −110\displaystyle -\frac{1}{10}−101.
Find the length of side ACACAC.
Find the exact area of the triangle.
217 exam-style questions on Edexcel A Level Maths Trigonometric Ratios, covering 9.1 The Cosine Rule, 9.2 The Sine Rule, 9.3 Areas of Triangles, 9.4 Solving Triangle Problems, 9.5 Graphs of Sine, Cosine and Tangent, and 9.6 Transforming Trigonometric Graphs. Each one has a worked solution and a mark scheme showing where the marks go.