How do you solve for h in $a = \dfrac{1}{2}bh?$

Hint:
For solving such types of questions, you first need to understand what the question means. In this question you just have to rearrange the equation. In complete step by step answer, a detailed solution is given.

Complete step by step solution:
Here, in this question you have $a = \dfrac{1}{2}bh$.
Now you have to solve for h.
For that we will rearrange this whole equation.
First, we will multiply both the side of equation by two,
So, after multiplying by two equation will become,
$2a = bh$
Now, we will multiply both the side of the equation by b.
So, after multiplying both the side of equation by two equation will become,

So, $\dfrac{{2a}}{b} = h$

Note:
In such a type of question you must first think, and after that figure out how you can solve questions in the best easy way. Always try to avoid long and difficult methods, because it is occurring in your time and sometimes you may not get the right answer.