In the given diagram, $WY$ and $WZ$ are straight lines, and $O$ is the center of the circle on the left. The angle $OWX$ is $48^\circ$. We are asked to find the angle $XYZ$.
2025/4/21
1. Problem Description
In the given diagram, and are straight lines, and is the center of the circle on the left. The angle is . We are asked to find the angle .
2. Solution Steps
Since is the center of the circle on the left and is a straight line, the points , , , and are collinear.
In triangle , since and are radii of the same circle, . Therefore, triangle is an isosceles triangle.
Since is an isosceles triangle with , the angles opposite these sides are equal, i.e., .
The sum of angles in a triangle is . In triangle , we have
Since and are supplementary angles, i.e., they form a straight line,
Since are points on the circle on the right, is a cyclic quadrilateral. The exterior angle of a cyclic quadrilateral is equal to the interior opposite angle. Also, the sum of opposite angles in a cyclic quadrilateral is . The angle at the center of a circle is twice the angle at the circumference when subtended by the same arc.
Consider the circle passing through , , . Since is a straight line, is a chord of the circle.
is the angle at the center subtended by the chord .
is the angle at the circumference subtended by the chord .