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  1. Maths
  2. Year 9
  3. Algebra: Expressions
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Algebraic Triangles

In this worksheet, students form and solve equations by adding together the algebraic angles shown in each triangle.

'Algebraic Triangles' worksheet

Key stage:  KS 3

Curriculum topic:   Geometry and Measures

Curriculum subtopic:   Interpret Mathematical Relationships Algebraically/Geometrically

Difficulty level:  

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Worksheet Overview

QUESTION 1 of 10

The angles in a triangle add to 180º.

This is no different when the angles are algebraic expressions.

 

Example

Form an equation from the angles shown in this triangle and solve it to find the value of a.

 

 

Answer

The sum of the angles = 180

a + 10 + a - 37 + a = 180

 

We simplify and solve this equation as follows:

3a - 27 = 180

3a = 207

a = 207 ÷ 3 = 69

a = 69

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

  • ANSWERS
  • Question 1

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

CORRECT ANSWER
20
EDDIE SAYS
3a + 4a + 2a = 180 9a = 180
  • ANSWERS
  • Question 2

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

CORRECT ANSWER
22
EDDIE SAYS
3a + 3a - 50 + 4a + 10 = 180 10a - 40 = 180
  • ANSWERS
  • Question 3

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

CORRECT ANSWER
35
EDDIE SAYS
4a - 65 + 2a + 10 + a -10 = 180 7a - 65 = 180
  • ANSWERS
  • Question 4

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

CORRECT ANSWER
30
EDDIE SAYS
2a + a + 40 + a + 20 = 180 4a + 60 = 180
  • ANSWERS
  • Question 5

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

CORRECT ANSWER
20
EDDIE SAYS
60 - a + 3a + 30 + 4a - 30 = 180 6a + 60 = 180
  • ANSWERS
  • Question 6

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

CORRECT ANSWER
11
EDDIE SAYS
5a + 3a + 30 + 2a + 40 = 180 10a + 70 = 180
  • ANSWERS
  • Question 7

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

CORRECT ANSWER
27.5
EDDIE SAYS
a - 50 + 4a + 10 + 3a = 180 8a - 40 = 180
  • ANSWERS
  • Question 8

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

CORRECT ANSWER
25
EDDIE SAYS
2a - 50 + 3a + 5 + 4a = 180 9a - 45 = 180
  • ANSWERS
  • Question 9

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

CORRECT ANSWER
21
EDDIE SAYS
4a - 50 + 3a + 4 + 100 - a = 180 6a + 54 = 180
  • ANSWERS
  • Question 10

Form an equation from the angles shown in this triangle and solve it to find the value of a.

(Just write the number)

 

CORRECT ANSWER
26
EDDIE SAYS
100 - a + 3a + 4 + 50 - a = 180 a + 154 = 180
---- OR ----

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