Maths · Year 5
Bell.Study
Angles & Geometry
Measuring, estimating and calculating angles; identifying angle types and using angle rules
- 1
What type of angle is 45°? A) Acute B) Right C) Obtuse D) Reflex
Answer: - 2
Is this statement true or false? A right angle measures exactly 90°. A) True B) False
Answer: - 3
An angle of 135° is what type of angle? 135° is an ___ angle.
Answer: - 4
How many degrees are there on a straight line? A) 90° B) 180° C) 270° D) 360°
Answer: - 5
Two angles on a straight line are 110° and x°. What is x? x = ___°
Answer: - 6
The three angles in a triangle are 60°, 80° and x°. What is x? A) 20° B) 40° C) 60° D) 80°
Answer: - 7
Label each angle type on this diagram showing four angles at a point.
Answer: - 8
Is this statement true or false? An isosceles triangle can have angles of 40°, 40° and 100°. A) True B) False
Answer: - 9
A quadrilateral has angles of 90°, 120° and 80°. What is the fourth angle? The fourth angle is ___°
Answer: - 10
Two angles on a straight line are in the ratio 1:2. What is the larger angle? A) 60° B) 90° C) 120° D) 150°
Answer:
Answer key
Angles & Geometry · for parents and teachers
- 1
Acute
An acute angle is less than 90°. Since 45° < 90°, it is acute.
- 2
True
A right angle is exactly 90° - like the corner of a rectangle.
- 3
obtuse
An obtuse angle is between 90° and 180°. Since 90° < 135° < 180°, it is obtuse.
- 4
180°
Angles on a straight line add up to 180° (two right angles).
- 5
70
Angles on a straight line sum to 180°. x = 180 - 110 = 70°.
- 6
40°
180° - 60° - 80° = 40°. Angles in a triangle sum to 180°.
- 7
z1: Acute; z2: Right; z3: Obtuse; z4: Reflex
Acute angles are less than 90°, right angles are exactly 90°, obtuse angles are between 90° and 180°, and reflex angles are greater than 180°.
- 8
True
40° + 40° + 100° = 180° ✓. Two angles are equal, so it is a valid isosceles triangle.
- 9
70
Angles in a quadrilateral sum to 360°. 360 - 90 - 120 - 80 = 70°.
- 10
120°
1 + 2 = 3 parts. 180° ÷ 3 = 60° per part. The larger angle = 2 × 60° = 120°.