Classifying Triangles by Sides and Angles
Name: _______________________________
Date: _______________________________
Remember:
By Sides:
- Equilateral: all 3 sides equal
- Isosceles: 2 sides equal
- Scalene: no sides equal
By Angles:
- Acute: all angles < 90°
- Right: one angle = 90°
- Obtuse: one angle > 90°
Part A: Classify by Sides
Write whether each triangle is equilateral, isosceles, or scalene.
1.
Triangle with sides: 5 cm, 5 cm, 5 cm
_______________________________
2.
Triangle with sides: 7 cm, 9 cm, 7 cm
_______________________________
3.
Triangle with sides: 4 cm, 6 cm, 8 cm
_______________________________
4.
Triangle with sides: 12 mm, 12 mm, 15 mm
_______________________________
5.
Triangle with sides: 3.5 m, 4.2 m, 5.1 m
_______________________________
Part B: Classify by Angles
Write whether each triangle is acute, right, or obtuse.
6.
Triangle with angles: 60°, 60°, 60°
_______________________________
7.
Triangle with angles: 45°, 45°, 90°
_______________________________
8.
Triangle with angles: 110°, 40°, 30°
_______________________________
9.
Triangle with angles: 55°, 65°, 60°
_______________________________
10.
Triangle with angles: 30°, 60°, 90°
_______________________________
Part C: Double Classification
Classify each triangle by BOTH sides and angles.
11.
Triangle with sides 8 cm, 8 cm, 8 cm and angles 60°, 60°, 60°
By sides: _____________________________ By angles: _____________________________
12.
Triangle with sides 5 m, 5 m, 7 m and angles 48°, 48°, 84°
By sides: _____________________________ By angles: _____________________________
13.
Triangle with sides 6 cm, 8 cm, 10 cm and angles 37°, 53°, 90°
By sides: _____________________________ By angles: _____________________________