d=3h2\displaystyle d = \sqrt{\frac{3h}{2}}d=23h
Show that 2d2=3h2d^2 = 3h2d2=3h.
Hence, make h h\,h the subject of the formula.
210 exam-style questions on Eduqas GCSE Maths Changing the Subject of a Formula. Each one has a worked solution and a mark scheme showing where the marks go.