How many sides does a triangle have?
Triangles are classified by their angles and side lengths. A triangle's angles can be acute, right, or obtuse. The sides of a triangle can be equal or different lengths.
Acute Triangle: A triangle with three angles that are all less than 90°. Right Triangle: A triangle with one angle that is 90°. Obtuse Triangle: A triangle with one angle that is greater than 90°.
Do you think triangles are easy to classify?
- I don't know
The longest side of an acute triangle is opposite the largest angle. The longest side of a right triangle is opposite the right angle. The longest side of an obtuse triangle is opposite the smallest angle.
Draw / write: What are the three different types of triangles?
Draw / write: What is the difference between acute and obtuse triangles?
How did you decide which type of triangle each example was?
What strategies did you use to classify the different types of triangles?