Question

The three angles of a quadrilateral are ${40}^{\circ },{80}^{\circ },{90}^{\circ }$. The fourth angle is:

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

According to the angle sum property of a quadrilateral, the sum of all the angles of a quadrilateral is $={360}^{\circ }$

$\therefore$The fourth angle

$={360}^{\circ }$-(${40}^{\circ }$+${80}^{\circ }$+${90}^{\circ }$)
$={360}^{\circ }-{210}^{\circ }$
$={150}^{\circ }$