Calculate Angle B in Triangle ABC: Given Obtuse Angle and A = 20°

To determine the angle $\angle B$ in triangle ABC with given $\angle A = 20^\circ$ and $\angle B > 90^\circ$, consider these facts:

The sum of all angles in any triangle is $180^\circ$.

With $\angle A = 20^\circ$, and knowing that $\angle B$ should be greater than $90^\circ$, mathematically, the sum of $\angle B$ and $\angle C$ should be $160^\circ$. However, without specific value for $\angle C$, multiple combinations of $\angle B$ and $\angle C$ that satisfy this condition exist.

To determine a unique value for $\angle B$, more information about $\angle C$ or any other angles or conditions is needed.

Thus, with the current information, it is not possible to calculate an exact measure for $\angle B$. Hence, the answer is No.