WJEC Unit 1 2019 June — Question 14 6 marks

Exam BoardWJEC
ModuleUnit 1 (Unit 1)
Year2019
SessionJune
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicSine and Cosine Rules
TypeGiven area find angle/side
DifficultyStandard +0.3 This is a straightforward application of the area formula (½ab sin C) and cosine rule. Students must use area = ½(5)(x)sin(120°) = 14 to find x, then apply the cosine rule to find y. While it requires two standard formulas and some algebraic manipulation, it's a routine multi-step question with no novel insight required, making it slightly easier than average.
Spec1.05b Sine and cosine rules: including ambiguous case1.05c Area of triangle: using 1/2 ab sin(C)

The diagram below shows a triangle \(ABC\) with \(AC = 5\) cm, \(AB = x\) cm, \(BC = y\) cm and angle \(BAC = 120°\). The area of the triangle \(ABC\) is \(14\) cm\(^2\). \includegraphics{figure_14} Find the value of \(x\) and the value of \(y\). Give your answers correct to 2 decimal places. [6]

The diagram below shows a triangle $ABC$ with $AC = 5$ cm, $AB = x$ cm, $BC = y$ cm and angle $BAC = 120°$. The area of the triangle $ABC$ is $14$ cm$^2$.

\includegraphics{figure_14}

Find the value of $x$ and the value of $y$. Give your answers correct to 2 decimal places. [6]

\hfill \mbox{\textit{WJEC Unit 1 2019 Q14 [6]}}