This book has been hailed as “the reason why Korea is strong in maths”; as you can see it offers a potentially useful application of trigonometry to the would be panchira maniac.
An inspired way of interesting pubescent schoolboys in the delights of mathematics?
The book from which these illustrations are drawn is apparently genuine, though strangely it does not appear to be widespread use amongst school authorities despite its obvious motivational advantages.
The title seems to be from the “Dream Science Laboratory” series, though it is not clear which.
The series in question is originally published in Japan, but clearly has appeal elsewhere (Korea may not have the visible culture of perversion Japan has, but it does have an incidence of rape six times that of Japan).
It is not clear whether the Korean edition is official or plagiarised.