# Using the phase diagram for CO_2, what phase is carbon dioxide in at -60"^@C and 15 atm pressure?

And then you literally just read it like any other graph: find your $x$ coordinate and find your $y$ coordinate.
$\left(x , y\right) \equiv \left(P , T\right) = \left(\text{15 atm", -60^@ "C}\right)$
And one should easily see that ${\text{CO}}_{2}$ is a solid at this $T$ and $P$, as it should be, left of its triple point temperature but higher up than the triple point pressure.