(a)[1]
$\cos y^\circ = -0.54$ with $90 \le y \le 180$. A solution of $\cos x^\circ = 0.54$ is $x = 57$, correct to the nearest whole number. Find $y$, correct to the nearest whole number.
(b)[2]
Solve the equation $\frac{5a - 2}{3} = 11$.
Mathematics 4024 · O Level · Right-angled triangles