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The angles inside a triangle are called interior angles.
∠J = 40^(∘), ∠Y = 20^(∘)
We can draw a triangle between Jamestown, Williamsburg, and Yorktown. Let's look at the map!
We are given that the interior angle at Williamsburg ∠W measures 120^(∘) and that the interior angle at Jamestown ∠J is twice the measure of the angle at Yorktown ∠Y. We can write the measurements for ∠J and ∠Y in terms of the variable x using the given relationship. m∠W = 120^(∘) , m∠J= 2x^(∘) , and m∠Y = x^(∘)
Next, we can find the measure of the interior angles at Jamestown and Yorktown. We will do this using the rule for the interior angle measures of a triangle.
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Interior Angle Measures of a Triangle |
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The sum of the interior angles of a triangle is 180^(∘). |
Using this rule, we can write the equation for the interior angles of the given triangle. 120^(∘) + 2x^(∘)+ x^(∘)=180^(∘) Now, let's solve the equation for x.
Add terms
LHS-120=RHS-120
.LHS /3.=.RHS /3.
We found that x=20. This means that the measure of interior angle at Yorktown is 20^(∘). We can substitute 20 for x to evaluate the expression for the interior angle at Jamestown.
The measure of the interior angle at Jamestown is 40^(∘).