Lesson details

Key learning points

  1. In this lesson, we will determine when it is impossible to construct a triangle given three lengths.

Licence

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5 Questions

Q1.
If you know the length of the sides of a triangle, you can _______ it using a pair of ______.
Correct answer: construct, compass
construct, protractor
draw, compass
make,ruler
Q2.
This circle is drawn on a centimetre square grid. State the radius and diameter.
An image in a quiz
Radius = 2cm, Diameter = 2cm
Correct answer: Radius = 2cm, Diameter = 4cm.
Radius = 4cm, Diameter = 2cm
Q3.
This circle is drawn on a centimetre square grid. State the radius and diameter.
An image in a quiz
Correct answer: R = 1cm, D = 2cm
R = 1cm; D = 1cm
R = 2cm; D = 1cm
Q4.
This circle is drawn on a centimetre square grid. State the radius and diameter.
An image in a quiz
Others
R = 4cm, D = 4cm
Correct answer: R = 4cm, D = 8cm.
R= 8cm, D = 4cm
Q5.
Two students were asked to construct a triangle with side lengths 3 cm , 2 cm and 4 cm. Are they both correct?
An image in a quiz
No, they are not both correct. Only B is correct because she mentioned the shortest angle first then measured the rest.
No, they are not both correct. Only student A is correct because the base is 3cm.
Correct answer: Yes, they are both correct because both of the triangles are identical (congruent) but they are orientated differently.

5 Questions

Q1.
When constructing a triangle, should you erase the construction lines at the end?
Correct answer: No
Some of them
Yes
Q2.
Which triangle is impossible to construct?
Correct answer: 5cm, 2cm, 3cm
6cm, 8cm, 3cm
7cm, 3cm, 9cm
All of them
Q3.
What equipment would you use to construct a 9cm, 7cm, 18cm triangle correctly?
Ruler and pencil
Correct answer: Ruler, pencil and compass
Ruler, pencil and protractor
Q4.
Which triangle is impossible to construct?
1cm, 1cm, 1cm
6cm, 2cm, 5cm
Correct answer: 8cm, 2cm, 6cm
Q5.
How do I know from the construction that this is an impossible triangle?
An image in a quiz
The base is 8cm. 4cm should have been the base.
Correct answer: The circles do not intersect.
The dotted line for 4cm is diagonal

Lesson appears in

UnitMaths / Constructing triangles and quadrilaterals