Geometry

Question Analysis

The main focus is using the property that an inscribed angle in a semi - circle is a right angle. Since is the diameter, . Also, because , is isosceles, and the non - right angles are equal. We'll set up an equation using the given angle expression and solve for .

 

Key Concept Explanation

1. An inscribed angle subtended by a diameter (in a semi - circle) is a right angle ().

2. In an isosceles triangle, the base angles are equal.

 

Step - by - Step Solution

1. Since is the diameter, in . And because , .

2. Using the triangle angle - sum theorem (...