What type of triangle appears in the drawing?
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What type of triangle appears in the drawing?
To determine which type of triangle we are dealing with, let's calculate angle alpha based on the fact that the sum of angles in a triangle is 180 degrees.
Since alpha is equal to 140 degrees, the triangle is an obtuse triangle.
Obtuse triangle
What kid of triangle is given in the drawing?
Easy memory trick: Acute = all angles less than 90° (sharp and small), Right = exactly one 90° angle (like a square corner), Obtuse = one angle greater than 90° (wide and "fat").
You need all three angles to classify correctly! The largest angle determines the type. In this problem, even though 30° and 10° are both acute, the third angle makes it obtuse.
Always double-check: add all three angles together. They must equal exactly 180°. If not, recalculate! For this triangle: ✓
Impossible! If two angles were each greater than 90°, their sum would exceed 180°. Since all three angles must total exactly 180°, only one angle can be obtuse.
Yes! Calculate the missing angle, then check:
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