# Constructing triangles

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## Lesson details

### Key learning points

- In this lesson, we will learn how to construct triangles using a pair of compasses and ruler given the length of the sides. We will need a pair of compasses, pencil and ruler for this lesson.

### Licence

This content is made available by Oak National Academy Limited and its partners and licensed under Oak’s terms & conditions (Collection 1), except where otherwise stated.

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### 6 Questions

Q1.

Label this part of the circle

Diameter

Radius

Tangent

Q2.

Label this part of the circle

Arc

Circumference

Radius

Q3.

Label this part of the circle

Arc

Circumference

Diameter

Q4.

What is the circumference of a circle?

The circumference is also the radius of a circle

The circumference is the area of the circle

Q5.

Complete the sentence. The diameter of a circle is...

Half the radius of the circle

Others

The length of the circle

The same as the radius of a circle

Q6.

The radius of my circle is 8.5cm. What is the diameter of the circle?

16cm

4.25cm

8.5cm

### 5 Questions

Q1.

If you know the length of the sides of a triangle, you can _______ it using a pair of ______.

construct, protractor

draw, compass

make,ruler

Q2.

This circle is drawn on a centimetre square grid. State the radius and diameter.

Radius = 2cm, Diameter = 2cm

Radius = 4cm, Diameter = 2cm

Q3.

This circle is drawn on a centimetre square grid. State the radius and diameter.

R = 1cm; D = 1cm

R = 2cm; D = 1cm

Q4.

This circle is drawn on a centimetre square grid. State the radius and diameter.

Others

R = 4cm, D = 4cm

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?

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.