Examples with solutions for Sum and Difference of Angles: Using variables

Exercise #1

B ∢B is 2 times bigger than A ∢A andC ∢C is 3 times bigger than B ∢B .

Calculate A ∢A .

AAABBBCCC3B

Video Solution

Answer

20°

Exercise #2

Look at triangle ABC below.

A+B=2C ∢A+∢B=2∢C

B=3A ∢B=3∢A

Calculate the size of angle C. \sphericalangle C\text{.} AAACCCBBBα

Video Solution

Answer

60°

Exercise #3

The triangle ABC is shown below.

angle A=70° ∢A=70° .

BC=13 \frac{∢B}{∢C}=\frac{1}{3}

Calculate angle C ∢C .

AAABBBCCC70°

Video Solution

Answer

82.5°

Exercise #4

The triangle ABC is shown below.

C=2B ∢C=2∢B

B=5A ∢B=5∢A

Calculate C ∢C .

CCCBBBAAA2∢B5∢A

Video Solution

Answer

5614° 56\frac{1}{4}°

Exercise #5

ABC is an isosceles triangle.

DE is parallel to BC.

Angle A is equal to 3X plus 22.

Express the size of angle DEC.

AAABBBCCCDDDEEE

Video Solution

Answer

101+1.5x 101+1.5x