We know that the sum of a straight line is 180° . So here there are 3 angles in a straight line . And the sum is 180° . So that ,
[tex]\tt\to Sum_{(angles \ of \ a \ straight \ line)}= 180^o \\\\\tt \to 7x + 8x + 44.4^o = 180^o \\\\\tt\to 15x = 180^o - 44.4^o \\\\\tt\to 15x = 135.6^o \\\\\tt\to x =\dfrac{135.6^o}{15}\\\\\tt\to \boxed{\orange{\tt x = 9.04^{\circ} \approx 9^{\circ} }}[/tex]
So the measure of angle that is highlighted will be 8x = 8(9) = 72°
