Triangles: Calculate Unknown Angles

In this worksheet, students use their knowledge of the properties of a triangle to evaluate unknown angles.

Key stage:  KS 2

Curriculum topic:   Geometry: Properties of Shapes

Curriculum subtopic:   Compare Shape Properties

Difficulty level:

QUESTION 1 of 10

In this worksheet, calculate the unknown angle in a triangle.

Question:

Calculate the unknown angle in the triangle.

Answer:

The angles in any triangle add to 180°.

Angle = 180° - 54° - 64° = 62°

The unknown angle is 62°.

Calculate the unknown angle.

Calculate the unknown angle.

Calculate the unknown angle.

Calculate the unknown angle.

Calculate the unknown angle.

Calculate the unknown angle.

Calculate the unknown angle.

Calculate the unknown angle.

Calculate the unknown angle.

Calculate the unknown angle.

• Question 1

Calculate the unknown angle.

CORRECT ANSWER
37
EDDIE SAYS
180 - 77 - 66 = 37
• Question 2

Calculate the unknown angle.

CORRECT ANSWER
32
EDDIE SAYS
180 - 69 - 79 = 32
• Question 3

Calculate the unknown angle.

CORRECT ANSWER
41
EDDIE SAYS
180 - 87 - 52 = 41
• Question 4

Calculate the unknown angle.

CORRECT ANSWER
39
EDDIE SAYS
180 - 74 - 67 = 39
• Question 5

Calculate the unknown angle.

CORRECT ANSWER
74
EDDIE SAYS
180 - 22 - 84 = 74
• Question 6

Calculate the unknown angle.

CORRECT ANSWER
64
EDDIE SAYS
180 - 90 - 26 = 64
• Question 7

Calculate the unknown angle.

CORRECT ANSWER
25
EDDIE SAYS
180 - 86 - 69 = 25
• Question 8

Calculate the unknown angle.

CORRECT ANSWER
62
EDDIE SAYS
180 - 54 - 64 = 62
• Question 9

Calculate the unknown angle.

CORRECT ANSWER
37
EDDIE SAYS
180 - 77 - 66 = 37
• Question 10

Calculate the unknown angle.

CORRECT ANSWER
41
EDDIE SAYS
180 - 87 - 52 = 41
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