Find the measure of the angle
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Find the measure of the angle
Let's remember that the sum of angles in a triangle is equal to 180 degrees.
Therefore, we will use the following formula:
Now let's input the known data:
We'll move the term to the other side and keep the appropriate sign:
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Is DE side in one of the triangles?
This is the Triangle Angle Sum Theorem - a fundamental property of triangles in flat (Euclidean) geometry. It works for any triangle: acute, obtuse, right, or scalene!
Check your arithmetic! Angles in triangles are always positive. If you get negative, you likely made a calculation error or the given angles don't form a valid triangle.
No! If two angles are each greater than 90°, their sum alone would exceed 180°. A triangle can have at most one obtuse angle.
Write the angle sum formula: . Then substitute the known values and solve for the unknown angle.
Then the three angles cannot form a triangle! Double-check your given values - there might be an error in the problem or your calculations.
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