Constructing triangles | Exit Quiz | Oak National Academy

Which description matches this sketch?

• Triangle PQR, where PQ = 7 cm, PR = 12 cm and QR = 14 cm

• Triangle PQR, where PQ = 7 cm, PR = 14 cm and QR = 12 cm

• Triangle PQR, where PQ = 12 cm, PR = 14 cm and QR = 7 cm

• Triangle PQR, where PQ = 14 cm, PR = 7 cm and QR = 12 cm

• Triangle PQR, where PQ = 14 cm, PR = 12 cm and QR = 7 cm

Answer explanation

If you were to sketch any of the descriptions, the physical size of the triangle would be correct but the vertices would be in the wrong positions.

When constructing a triangle from three edge lengths, we use a pair of compasses to draw ___ circles.

Answer explanation

The three edge lengths are the radii of the circles/arcs that are being drawn using the pair of compasses.

Which of the following shows a partial construction of an equilateral triangle?

• 
• 
• 
• 

Answer explanation

To finish the construction, the point of intersection needs to be joined to the ends of the base edge with line segments.

Which of the following lengths could be the edge lengths of a triangle?

• 3 cm, 4 cm and 5 cm

• 3 cm, 3 cm and 6 cm

• 8 cm, 8 cm and 8 cm

• 7 cm, 9 cm and 18 cm

• 9 cm, 9 cm and 14 cm

Which of the points C, D or E when connected to AB would create a triangle with three edges of different lengths?

• C

• D

• E

Answer explanation

If each circle's radius is one unit more each time, then the edges of triangle ABC are 5 units, 3 units and 4 units. This is a right-angled scalene triangle.

Triangle ABE is an ___ triangle.

Answer explanation

As two of the edges of triangle ABE are equal, it is an isosceles triangle.