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Year 8 · Key Stage 3 · free KS3 maths worksheet

Constructions

12 original questions, 31 marks. Type your answers below for an instant mark and a score (algebra in any equivalent form, e.g. 2sqrt(3) or 2√3), or print the worksheet, mark it with the answers sheet, and use the solutions to see every step written out by hand.

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The questions

1

Draw a line segment AB of length 8 cm.

Using a ruler and compasses only, construct the perpendicular bisector of AB.

You must show all your construction lines.

AB
2 marks
Show answer
Arcs of equal radius (more than 4 cm) drawn from A and from B, crossing above and below AB; the straight line through the two crossing points is the perpendicular bisector, cutting AB at its midpoint at 90 degrees
2

The diagram shows angle ABC.

Using a ruler and compasses only, construct the bisector of angle ABC.

You must show all your construction lines.

Then use a protractor to measure one of the two angles your bisector makes.

ABC
2 marks
Show answer
Arc from B crossing both arms, equal arcs from those two points crossing inside the angle, line from B through the crossing; each half measures 38° (accept 36° to 40°)
3

Using a ruler and compasses only, construct an isosceles triangle ABC in which AB = 7 cm and AC = BC = 5 cm.

You must show all your construction arcs.

AB
2 marks
Show answer
Draw AB = 7 cm; arcs of radius 5 cm from A and from B cross at C; joining AC and BC gives the required isosceles triangle
4

Here is a sketch of an equilateral triangle with sides of 6 cm.

Using a ruler and compasses only, construct the triangle accurately in the space below. You must show all your construction arcs.

Write down the size of each angle in your triangle.

ABC6 cm6 cm6 cmDiagram NOT accurately drawn
2 marks
Show answer
Base 6 cm, arcs of radius 6 cm from each end crossing at the third vertex; each angle is 60°
5

Draw a straight line 10 cm long. Mark a point M on the line, about halfway along.

Using a ruler and compasses only, construct the line perpendicular to the line at the point M.

You must show all your construction lines.

M
2 marks
Show answer
Equal arcs from M crossing the line either side at X and Y, then larger equal arcs from X and Y crossing above the line; the line through M and that crossing point is perpendicular to the original line at M
6

The diagram shows a line AB.

Using a ruler and compasses only, construct an angle of 60° at A.

You must show all your construction arcs.

AB
2 marks
Show answer
Arc from A crossing AB at X, arc of the same radius from X crossing the first arc; the line from A through that crossing point makes 60° with AB
7

Draw a straight line 10 cm long. Mark a point P about 4 cm above the line.

Using a ruler and compasses only, construct the perpendicular from P to the line.

You must show all your construction lines.

P
2 marks
Show answer
An arc from P crossing the line at two points, then arcs of equal radius from those two points crossing below the line; the line from P through that crossing point is perpendicular to the original line
8

The diagram shows a straight line with a point A marked on it.

Using a ruler and compasses only, construct an angle of 45° at A.

You must show all your construction lines.

A
3 marks
Show answer
Construct the perpendicular to the line at A (90°), then bisect the 90° angle; the bisector makes 45° with the line
9

The diagram shows a tree T in a field and a straight fence.

Ellie wants to walk from the tree to the fence by the shortest possible route.

  1. Using a ruler and compasses only, construct the shortest route from T to the fence. You must show all your construction lines.
  2. Explain why this route is the shortest.
Tfence
3 marks
Show answer
a) open: The perpendicular from T to the fence, found by an arc from T cutting the fence twice and equal arcs from those points crossing on the other side b) open: The shortest distance from a point to a line is along the perpendicular, which meets the line at 90°
10

Here is a sketch of triangle ABC.

AB = 7 cm, AC = 5 cm and angle BAC = 60°.

Using a ruler and compasses only, construct triangle ABC accurately. You must show all your construction arcs.

ABC7 cm5 cm60°Diagram NOT accurately drawn
3 marks
Show answer
AB = 7 cm drawn, 60° at A constructed with two arcs of equal radius, C marked 5 cm along that line with compasses, then C joined to B
11

Here is a sketch of triangle PQR.

PQ = 8 cm, angle QPR = 45° and angle PQR = 60°.

  1. Using a ruler and compasses only, construct triangle PQR accurately. You must show all your construction lines.
  2. Work out the size of angle PRQ. Check your answer by measuring your drawing.
PQR8 cm45°60°Diagram NOT accurately drawn
4 marks
Show answer
a) open: PQ = 8 cm; 45° at P by bisecting a constructed right angle; 60° at Q by two equal arcs; R where the lines cross b) 75°
12

PQRS is a rhombus. Each side of the rhombus is 5 cm long. The diagonal PR is 8 cm long.

  1. Using a ruler and compasses only, construct the rhombus PQRS accurately. You must show all your construction arcs.
  2. Measure the length of the other diagonal, QS.
PQRS5 cm5 cm5 cm5 cm8 cmDiagram NOT accurately drawn
4 marks
Show answer
a) open: PR = 8 cm drawn; arcs of radius 5 cm from P and from R cross above the line at Q and below at S; join PQ, QR, RS, SP b) 6 cm

Your score

Answer the questions above and your score appears here.

Every question here is original and written by Robinson Tuition. It follows the Key Stage 3 programme of study; Year 9 sheets end with extension questions for top sets.

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