[tex]m\angle B\text{ = 24 }[/tex]
Here, we want to calculate the measure of angle B
Mathematically, when two angles lie on a straight line, they are supllementary. What this mean is that they add up to 180 degrees
Thus, we have it that;
[tex]m\angle A\text{ + m}\angle B\text{ = 180}[/tex]
From the question, we have that;
[tex]m\angle A\text{ = 5(m}\angle B\text{ + 7.2)}[/tex]
Now, we substitute the value of the measure of angle A into the equation above
We have this as;
[tex]\begin{gathered} m\angle B\text{ + 5(m}\angle B\text{ + 7.2) = 180} \\ m\angle B\text{ + 5m}\angle B\text{ + 36 = 180} \\ 6m\angle B\text{ = 180-36} \\ 6m\angle B\text{ = 144} \\ m\angle B\text{ = }\frac{144}{6} \\ \\ m\angle B\text{ = 24} \end{gathered}[/tex]
