Question

The three angles of a quadrilateral are 60ᵒ ,80ᵒand 120ᵒ.find the fourth angle.

Answer 1

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$\underline{ \frak{ \purple{question}}}$

The three angles of a quadrilateral are 60° , 80° and 120° . find the fourth angle.

$\underline{ \frak{ \purple{solution}}}$

The sum of all angles of quadrilateral = 360°

let the unknown angle be x

then,

x + 60° + 80° + 120° = 360°

x + 260° = 360°

x = 360° - 260°

$\boxed{ \tt \: x = 100\degree}$

Hence, the fourth angle of quadrilateral be 100° .

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Answer 2

Answer:

let the fourth angle be X degree

and the other three angles are 60°80°120°

we know the sum of all angles of quadrilateral is 360°

60+80+120+X=360

260+X=360

X=360-260

X=100

the value of fourth angle is 100°