Three angles of a quadrilateral are $ 75^{\circ}, 90^{\circ} $ and $ 75^{\circ}. The fourth angle is(a) $ 90^{\circ} $
(b) $ 95^{\circ} $
(c) $ 105^{\circ} $
(d) $ 120^{\circ} $
Given:
Three angles of a quadrilateral are $75^o, 90^o$ and $75^o$.
To do:
We have to find the fourth angle.
Solution:
We know that,
Sum of the angles in a quadrilateral is $360^o$.
Let the fourth angle be x.
Therefore,
$75^o+90^o+75^o+x=360^o$
$x+240^o=360^o$
$x=360^o-240^o=120^o$
The fourth angle of the quadrilateral is $360^o$.
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