Question

If you're good at exact values of trig ratios pea shell me with 13a

Answer 1

It is an equilateral triangle so its angles are equal 60°. From the definition, we know that:

$\sin60^\circ=\dfrac{h}{4}$

and

$\sin60^\circ=\dfrac{\sqrt{3}}{2}$

so

$\dfrac{\sqrt{3}}{2}=\dfrac{h}{4}\quad \Big|\cdot4\\\\\\h=\dfrac{4\cdot\sqrt{3}}{2}\\\\\boxed{h=2\sqrt{3}}$