Question

Find the size of unknown angle
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Answer 1

Answer: 75 degrees

Explanation:

Do you see how both sides of the angle come together to form the straight line seen at the bottom? This means that these are supplementary angles.

Supplementary Angles: Both sides have to add up to a total of 180 degrees.

With this, form an equation: x+(x+30)= 180

Get rid of the parenthesis:

x+x+30= 180

Combine like terms.

2x+30= 180

2x= 180-30

2x= 150

x= 150÷2

x= 75

Checks:

x+x+30= 180

75+75+30= 180

You can also check using the equation in its simplified form: 2x+30= 180.

2x+30=180

2(75)+30=180

150+30=180

Hence x=75

Answer 2

x° = 75

(x + 30)° = 105°

Explanation:

supplementary angle is two angles that sum is 180°

x° + (x + 30)° = 180°

2x + 30 = 180°

2x + 30 - 30 = 180 - 30

2x = 150

2x / 2 = 150 / 2

x° = 75

plug in 75,

75 + 30 = 105

check: 75 + 105 = 180