AI generatedGeometry and measuresKS3 / GCSE

Classifying triangles by sides

Classifying triangles by sides.

  • Use the stated properties and diagram markings, rather than judging by appearance.
  • Matching ticks mean equal lengths; matching arrows mean parallel lines.
  • A small square marks a right angle. Keep labels horizontal and include units.

Example 1

Classify the triangle by its side lengths. Lengths are in cm.

Geometry diagramABCDiagram not to scale
Equilateral.

Three equal sides: equilateral. At least two equal sides: isosceles. No equal sides: scalene.

Example 2

Classify the triangle by its side lengths. Lengths are in cm.

Geometry diagramPQRDiagram not to scale
Isosceles.

Three equal sides: equilateral. At least two equal sides: isosceles. No equal sides: scalene.

Your turn

Question 1

Classify the triangle by its side lengths. Lengths are in cm.

Geometry diagramABCDiagram not to scale
Check answer
Scalene.

Three equal sides: equilateral. At least two equal sides: isosceles. No equal sides: scalene.

Question 2

Classify the triangle by its side lengths. Lengths are in cm.

Geometry diagramPQRDiagram not to scale
Check answer
Equilateral.

Three equal sides: equilateral. At least two equal sides: isosceles. No equal sides: scalene.

Question 3

Classify the triangle by its side lengths. Lengths are in cm.

Geometry diagramABCDiagram not to scale
Check answer
Isosceles.

Three equal sides: equilateral. At least two equal sides: isosceles. No equal sides: scalene.

Question 4

Classify the triangle by its side lengths. Lengths are in cm.

Geometry diagramPQRDiagram not to scale
Check answer
Scalene.

Three equal sides: equilateral. At least two equal sides: isosceles. No equal sides: scalene.

Question 5

Classify the triangle by its side lengths. Lengths are in cm.

Geometry diagramABCDiagram not to scale
Check answer
Equilateral.

Three equal sides: equilateral. At least two equal sides: isosceles. No equal sides: scalene.

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