(a)[1]
State the mathematical name of this solid.
(b(i))[1]
Find the size of angle $x$.
(b(ii))[1]
State the mathematical name of this type of angle.
(c(i))[1]
Explain why angle $ACB$ is $90^{\circ}$.
(c(ii))[2]
Find the circumference of the circle.
(c(iii))[3]
Show that $AC$ is $9.8$ cm, correct to 2 significant figures.
(d)[3]
Find the radius of the sphere.