Last lesson we looked at how to draw triangles
Description: Last lesson we looked at how to draw triangles given two sides and an included angle: These are referred to as SAS triangles. Side, Angle, Side A We also looked at how to draw triangles given two angles and a side: These are referred to as
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slide1. Last lesson we looked at how to draw triangles given two sides and an included angle:
These are referred to as SAS triangles.
Side, Angle, Side A<br>
slide2. We also looked at how to draw triangles given two angles and a side:
These are referred to as ASA triangles.
Angle, Side, Angle A A<br>
slide3. Consider the Side, Side, Side triangle
Which piece of information would you start with? SSS<br>
slide4. Consider the Side, Side, Side triangle
If these angles are unknown, how can we draw the triangle? SSS<br>
slide5. Construct a triangle of side lengths 8 cm, 7 cm and 6 cm 1. Draw a straight line 8 cm long. Make sure you label the line. A B 8 cm<br>
slide6. Construct a triangle of side lengths 8 cm, 7 cm and 6 cm 2. Set the compass to 7 cm. Place the point at one end of the line and draw an arc. A B 8 cm<br>
slide7. Construct a triangle of side lengths 8 cm, 7 cm and 6 cm 3. Set the compass to 6 cm. Place the point at the other end of the line and draw an arc. A B 8 cm<br>
slide8. Construct a triangle of side lengths 8 cm, 7 cm and 6 cm 4. Draw straight lines from A and B to the point of intersection.
Keep the construction lines. A B 8 cm 7 cm 6 cm<br>
slide9. Constructing SSS triangles Construct a triangle of side lengths 7 cm and 9 cm and 4 cm Is this the only way we can draw this triangle? A B 9 cm 7 cm 4 cm<br>
slide10. How do we know they’re definitely the same triangle?<br>
slide11. 1) Construct this triangle. Measure angle ABC.
2) An isosceles triangle has 2 sides of length 8cm and one side of length 4cm.
Find the sizes of all the angles in the triangle.
3) Draw an equilateral triangle with sides of length 4cm. In your books..<br>
slide12. 4) Draw triangles with lengths 3, 4, 5 cm and 5, 12, 13 cm.
What type of triangles are these?
5) Draw a triangle with lengths 3, 4 and 7 cm.
What happens?
Can you explain why?
6) Draw a triangle with lengths 3, 4 and 8 cm.
What happens this time?
Can you explain why?
7) Can you make a conjecture about what must be true in order to draw an SSS triangle? In your books..<br>
These are referred to as SAS triangles.
Side, Angle, Side A<br>
slide2. We also looked at how to draw triangles given two angles and a side:
These are referred to as ASA triangles.
Angle, Side, Angle A A<br>
slide3. Consider the Side, Side, Side triangle
Which piece of information would you start with? SSS<br>
slide4. Consider the Side, Side, Side triangle
If these angles are unknown, how can we draw the triangle? SSS<br>
slide5. Construct a triangle of side lengths 8 cm, 7 cm and 6 cm 1. Draw a straight line 8 cm long. Make sure you label the line. A B 8 cm<br>
slide6. Construct a triangle of side lengths 8 cm, 7 cm and 6 cm 2. Set the compass to 7 cm. Place the point at one end of the line and draw an arc. A B 8 cm<br>
slide7. Construct a triangle of side lengths 8 cm, 7 cm and 6 cm 3. Set the compass to 6 cm. Place the point at the other end of the line and draw an arc. A B 8 cm<br>
slide8. Construct a triangle of side lengths 8 cm, 7 cm and 6 cm 4. Draw straight lines from A and B to the point of intersection.
Keep the construction lines. A B 8 cm 7 cm 6 cm<br>
slide9. Constructing SSS triangles Construct a triangle of side lengths 7 cm and 9 cm and 4 cm Is this the only way we can draw this triangle? A B 9 cm 7 cm 4 cm<br>
slide10. How do we know they’re definitely the same triangle?<br>
slide11. 1) Construct this triangle. Measure angle ABC.
2) An isosceles triangle has 2 sides of length 8cm and one side of length 4cm.
Find the sizes of all the angles in the triangle.
3) Draw an equilateral triangle with sides of length 4cm. In your books..<br>
slide12. 4) Draw triangles with lengths 3, 4, 5 cm and 5, 12, 13 cm.
What type of triangles are these?
5) Draw a triangle with lengths 3, 4 and 7 cm.
What happens?
Can you explain why?
6) Draw a triangle with lengths 3, 4 and 8 cm.
What happens this time?
Can you explain why?
7) Can you make a conjecture about what must be true in order to draw an SSS triangle? In your books..<br>