Answer: The correct option is (B) 81°.
Step-by-step explanation: We are given to find the measure of the missing angle of the quadrilateral shown in the figure.
The measures of three angles of the quadrilateral are 65°, 78° and 136°.
To find the value of x, the measure of the fourth angle.
We know that
the sum of the measures of four angles of a quadrilateral is 360°. so, we must have
[tex]65^\circ+78^\circ+136^\circ+x=360^\circ\\\\\Rightarrow 279^\circ+x=360^\circ\\\\\Rightarrow x=360^\circ-279^\circ\\\\\Rightarrow x=81^\circ.[/tex]
Thus, the measure of the missing angle is 81°.
Option (B) is CORRECT.
