View largerTypes of triangles chart
Triangles named by their sides (equilateral, isosceles, scalene) and by their angles (acute, right, obtuse)
1 page33 KB
Types of Triangles
A types of triangles chart, then naming triangles by sides and by angles, finding right triangles, drawing triangles and which triangles can exist.
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Types of triangles
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View all 2 pagesTriangles by angles
Naming triangles as acute, right or obtuse by looking at their largest angle
Answer key on page 2
2 pages33 KB
View all 2 pagesTriangles by sides
Naming triangles as equilateral, isosceles or scalene by their equal sides (tick marks show equal sides)
Answer key on page 2
2 pages35 KB
View all 2 pagesName the triangle two ways
Naming each triangle by its sides and by its angles using its angle measures and tick marks
Answer key on page 2
2 pages38 KB
View all 2 pagesFind the right triangles
Finding right triangles in any position by checking each corner for a right angle
Answer key on page 2
2 pages34 KB
View all 2 pagesDraw triangles
Drawing right, acute, obtuse, isosceles and scalene triangles on dot paper
Answer key on page 2
2 pages32 KB
View all 2 pagesCan the triangle Exist?
Reasoning about which mixes of side types and angle types can make a triangle
Answer key on page 2
2 pages49 KB
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About these types of triangles worksheets
Triangles are named in two ways. By their sides: an equilateral triangle has 3 equal sides, an isosceles triangle has at least 2 equal sides, and a scalene triangle has no equal sides. By their angles: an acute triangle has 3 angles less than 90°, a right triangle has one 90° angle, and an obtuse triangle has one angle greater than 90°.
Every triangle has one name of each kind, such as a right isosceles triangle (half of a square) or an obtuse scalene triangle. The three angles of any triangle add up to 180°, so no triangle can have two right angles or two obtuse angles.
On these worksheets, tick marks show equal sides and a small square shows a right angle. Every triangle is built from its angle measures, and its type is worked out from its sides and angles, so the pictures and the answer keys agree.
Standards
CCSS.MATH.CONTENT.4.G.A.2Classify two-dimensional figures based on the presence or absence of parallel or perpendicular lines, or the presence or absence of angles of a specified size. Recognize right triangles as a category, and identify right triangles.
How to use them
- Teach from the Types of Triangles Chart.
- Use Triangles by Angles and Triangles by Sides, then Name the Triangle Two Ways.
- Use Find the Right Triangles with the corner of a card.
- Finish with Draw Triangles and Can the Triangle Exist?
Teaching tips
- Look at the largest angle to name a triangle by its angles.
- Every equilateral triangle is also isosceles.
- Turned triangles are still the same type; check each corner.
Questions teachers and parents ask
What are the 6 types of triangles?
By sides: equilateral, isosceles and scalene. By angles: acute, right and obtuse. Each triangle has one of each, like an acute isosceles triangle.
Can a triangle be right and isosceles?
Yes. A right isosceles triangle has a 90° angle and two equal sides, like a square cut along its diagonal.
Can an equilateral triangle have a right angle?
No. Every angle of an equilateral triangle is 60°.