Given:
PQRS is a circle, PQT and SRT are straight lines.
To find:
The value of x.
Solution:
Since PQRS is a circle, PQT and SRT are straight lines, therefore, PQRS isa cyclic quadrilateral.
We know that, sum of opposite angles of a cyclic quadrilateral is 180 degrees.
[tex]m\angle SPQ+m\angle QRS=180^\circ[/tex]
[tex]81^\circ+m\angle QRS=180^\circ[/tex]
[tex]m\angle QRS=180^\circ-81^\circ[/tex]
[tex]m\angle QRS=99^\circ[/tex]
Now, SRT is a straight line.
[tex]m\angle QRT+m\angle QRS=180^\circ[/tex] (Linear pair)
[tex]m\angle QRT+99^\circ=180^\circ[/tex]
[tex]m\angle QRT=180^\circ-99^\circ[/tex]
[tex]m\angle QRT=81^\circ[/tex] ...(i)
According to the Exterior angle theorem, in a triangle the measure of an exterior angle is equal the sum of the opposite interior angles.
Using exterior angle theorem in triangle QRT, we get
[tex]m\angle PQR=m\angle QRT+m\angle QTR[/tex]
[tex]x=81^\circ+22^\circ[/tex]
[tex]x=103^\circ[/tex]
Therefore, the value of x is 103 degrees.
