Question

the three angles of a quadrilateral are 60dgrees, 80degrees and 120 degrees and find the 4th angle​

Answer 1

$\large\sf\underline{Solving\::}$

Given :-

• First angle = 60°

• Second angle = 80°

• Third angle = 120°

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To find :-

• The fourth angle

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Answer :-

From the angle sum property of quadrilateral we know :

✪ First angle + Second angle + Third angle + Fourth angle = 360°

• Substituting the values we are given

=> 60° + 80° + 120° + Fourth angle = 360°

=> 140° + 120° + Fourth angle = 360°

=> 260° + Fourth angle = 360°

=> Fourth angle = 360° - 260°

=> Fourth angle = 100°

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Thnks :)

Answer 2

$\huge \rm{ \underline{ \underline \pink{required \: answer}}}$

Given :-

• The three angles of quadrilateral are 60dgrees, 80degrees and 120 degrees.

To Find :

• The fourth angle

Solution :-

(As we know that sum of quadrilateral angles = 360°)

$\rm{let \: the \: fourth \: angle \: be \: y}$

$: \implies \rm{60 \degree + 80 \degree + 120 \degree + y = 360 \degree}$

$: \implies \rm{260 \degree + y = 360 \degree}$

$: \implies \rm{y = 360 \degree - 260 \degree}$

$: \implies{ \boxed {\underline{y = 100 \degree}}}$

$\rm{ \therefore \: the \: fourth \: quadrilateral \: angle \: is \: 100 \degree}$

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Additional information

• All polygon with four sides is called a quadrilateral. The sum of the measure of the four angles is 360° degree.

NOTE: Please refer to the attachment!