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In a polygon, the sum of the measures of the exterior angles — one at each vertex — is 360^(∘).
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We are given the following diagram.
We are asked to find the value of x. Notice that the x^(∘) angle is one of the exterior angles of the polygon in the diagram. To find the measure of the x^(∘) angle, we will first recall an important piece of information.
Exterior Angles of a Polygon |
In a polygon, the sum of the measures of the exterior angles — one at each vertex — is 360^(∘). |
This means that the sum of the exterior angles of the given triangle is also 360^(∘). Let's mark an exterior angle at each vertex of this triangle.
The exterior angles of the triangle have measures of x^(∘), 150^(∘), and y^(∘). These measures add up to 360^(∘). x^(∘) + 150^(∘) + y^(∘) = 360^(∘) We can use this equation to find the value of x, but we need to find the value of y first. Notice that the y^(∘) angle and the 100^(∘) angle form a straight line.