Calculate
(i)     the length of AC;
(ii)    the length of VC.

Calculate the angle between VC and the base ABCD.

(i)     $\sqrt {{{15}^2} + {{20}^2}}$     (M1)

Note: Award (M1) for correct substitution in Pythagoras Formula.

${\text{AC}} = 25{\text{ (cm)}}$     (A1)     (C2)

(ii)    $\sqrt {{{12.5}^2} + {{30}^2}}$     (M1)

Note: Award (M1) for correct substitution in Pythagoras Formula.

${\text{VC}} = 32.5{\text{ (cm)}}$     (A1)(ft)     (C2)

Note: Follow through from their AC found in part (a).

$\sin {\text{VCN}} = \frac{{30}}{{32.5}}$     OR     $\tan {\text{VCN}} = \frac{{30}}{{12.5}}$     OR     $\cos {\text{VCN}} = \frac{{12.5}}{{32.5}}$     (M1)
${ = 67.4^ \circ }$ ($67.3801 \ldots$)     (A1)(ft)     (C2)

Note: Accept alternative methods. Follow through from part (a) and/or part (b).