Math Problem Statement
Solution
The problem asks to work out the size of angle , where , , , and are points on the circumference of a circle. We are given that:
- ,
- , and
- .
Let’s go step by step to solve this problem:
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Isosceles Triangle : Since , triangle is isosceles. Therefore, the base angles of this triangle are equal. Let’s denote the two equal base angles as .
Since the sum of angles in a triangle is , we have: Solving for :
So, .
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Isosceles Triangle : Similarly, since , triangle is also isosceles. Let’s denote the base angles as .
The angle at is given as .
Now using the triangle angle sum property: Solving for :
So, .
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Cyclic Quadrilateral : Since , , , and are on the circumference, quadrilateral is a cyclic quadrilateral. The opposite angles of a cyclic quadrilateral sum to . Hence, we have: We already know that (from step 2), so: Solving for :
Thus, the size of is 102°.
Would you like more details on any of the steps? Here are five related questions to deepen understanding:
- Why is a triangle with two equal sides called isosceles, and how does it affect the angles?
- How do we know that the sum of the angles in any triangle is always 180°?
- Can the properties of cyclic quadrilaterals be applied to any other geometric shape?
- What other properties do isosceles triangles have, apart from equal angles opposite the equal sides?
- How does the Circle Theorem help solve problems involving angles in circles?
Tip: Always look out for isosceles triangles in geometry problems—they often help simplify angle calculations!
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Math Problem Analysis
Mathematical Concepts
Geometry
Circle Theorems
Isosceles Triangles
Cyclic Quadrilaterals
Formulas
Sum of angles in a triangle = 180°
Sum of opposite angles in a cyclic quadrilateral = 180°
Theorems
Circle Theorems
Isosceles Triangle Theorem
Cyclic Quadrilateral Theorem
Suitable Grade Level
Grades 9-11