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## वर्ग 7 (Foundation)

### Course: वर्ग 7 (Foundation)>Unit 3

Lesson 2: Types of triangles

# Classifying triangles by angles

You say you can't categorize a triangle because you don't know the length of the sides. Guess what? If you know the size of the angles you can! Created by Sal Khan.

## Want to join the conversation?

• What does the actual word "isosceles" mean?
• Isos is Greek for 'equal', and skelos is Greek for 'leg'. The Greek word isoskeles changed into the English word 'isoceles', so the literal definition is 'equal legs'.
• Why does a triangle's angles always add up to 180 degrees?
• One of the properties of a triangle is that all of it's angles add to 180 degrees. You can picture it as putting the angle measures together to form a line, which is also 180 degrees.
• What if a triangle has and right angle in it what type of triangle is it ?
• It is a "right" triangle, with ONLY one right angle.
• is equalateral triangle can have different angles
• An equilateral triangle's angles are all equal. It also has sides of equal length.
• What does equilateral mean?
• Equilateral means the shape or objects sides are the same in length.
• Is equal the same as congruent, or are do they have different meanings?
• 'Congruent' refers to two or more figures (not necessarily planar) which can exactly be superimposed on each other using tools: TRANSLATION, ROTATION, REFLECTION (and not dialation!).

'Equal' refers to magnitudes or numbers. Line segments can be compared equal by lengths (which also means that they are congruent). Other figures can be compared equal by areas and volumes and perimeters.

Get it? That's an interesting question. If you want (new) answers, ask intelligent questions like this.
• yea what does isosceles mean? ...
• In geometry, an isosceles triangle is a triangle that has two sides of equal length. Sometimes it is specified as having two and only two sides of equal length, and sometimes as having at least two sides of equal length.
• what if there's a square would an equilateral have 4 equal sides?
• Yes I think ot would. It is called a square.