Triangles
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A triangle has three sides and three angles
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The three angles always add to 180°
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Equilateral, Isosceles and Scalene
There are three special names given to triangles that tell how many sides (or angles) are equal.
There can be 3, 2 or no equal sides/angles:
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Equilateral Triangle
Three equal sides
Three equal angles, always 60°
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Isosceles Triangle
Two equal sides
Two equal angles
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Scalene Triangle
No equal sides
No equal angles
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What Type of Angle?
Triangles can also have names that tell you what type of angle is inside:
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Acute Triangle
All angles are less than 90°
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Right Triangle
Has a right angle (90°)
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Obtuse Triangle
Has an angle more than 90°
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Combining the Names
Sometimes a triangle will have two names, for example:
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Right Isosceles Triangle
Has a right angle (90°), and also two equal angles
Can you guess what the equal angles are?
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