Calculate the size of angle X given that the triangle is equilateral.
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Calculate the size of angle X given that the triangle is equilateral.
Remember that the sum of angles in a triangle is equal to 180.
In an equilateral triangle, all sides and all angles are equal to each other.
Therefore, we will calculate as follows:
We divide both sides by 3:
60
What kid of triangle is given in the drawing?
Equilateral triangles have all three sides equal AND all three angles equal (60° each). Isosceles triangles have only two equal sides and two equal angles.
Since all three angles are equal, we can write , which gives us . Dividing by 3:
Not really! Once you know it's an equilateral triangle, you can immediately say each angle is 60°. But setting up the equation helps you understand why it's always 60°.
Trust the given information! Even if the triangle doesn't look perfectly equilateral in the drawing, if the problem states it's equilateral, then all angles are 60°.
Never! By definition, equilateral triangles always have three 60° angles. If any angle is different, it's not equilateral anymore.
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