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In the figure above, PQRS is a circle. If PQT and SRT
are straight lines, find the value of x.

In the figure above, PQRS is a circle. If PQT and SRT are straight lines, find the-example-1
User Tls Chris
by
3.4k points

1 Answer

9 votes

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.


m\angle SPQ+m\angle QRS=180^\circ


81^\circ+m\angle QRS=180^\circ


m\angle QRS=180^\circ-81^\circ


m\angle QRS=99^\circ

Now, SRT is a straight line.


m\angle QRT+m\angle QRS=180^\circ (Linear pair)


m\angle QRT+99^\circ=180^\circ


m\angle QRT=180^\circ-99^\circ


m\angle QRT=81^\circ ...(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


m\angle PQR=m\angle QRT+m\angle QTR


x=81^\circ+22^\circ


x=103^\circ

Therefore, the value of x is 103 degrees.

User Corey Waldon
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