Question

Three angles of a quadrilateral are $75º,90ºand75º$. The fourth angle is

• A. $90º$
• B. $95º$
• C. $105º$
• D. $120º$

Answer 1

The correct option is D

$120º$

According to the given details

Three angles of a quadrilateral are $75°,90°and75°$

Let us assume the fourth angle to be $x$.

We know that according to the quadrilateral angle sum property, the sum of all the four interior angles is $360$ degrees.

$Sumofallanglesofaquadrilateral=360°$

$\Rightarrow 75°+90°+75°+x=360°$

$\Rightarrow 240°+x=360°$

$\Rightarrow x=360°–240°$

$\Rightarrow x=120°$

Hence, the fourth angle is $120°$.