(a) \(\frac{w}{360}\pi r^2=r^2\Rightarrow w=360/\pi\approx114.6^\circ\). (b) Subtract the two radii to obtain arc length \(7\pi r/10\). Hence \(\frac{x}{360}(2\pi r)=\frac{7\pi r}{10}\Rightarrow x=126^\circ\). (c) The base is \(q\sqrt3\). The cosine rule gives \(3q^2=q^2+q^2-2q^2\cos y\Rightarrow\cos y=-1/2\). Therefore \(y=120^\circ\).