A) \[\angle D\ge {{90}^{\text{o}}}\]
B) \[\angle D<{{90}^{\text{o}}}\]
C) \[\angle D\le {{90}^{\text{o}}}\]
D) \[\angle D>{{90}^{\text{o}}}\]
Correct Answer: B
Solution :
[b] \[\angle A+\angle B=180{}^\circ -\angle C+180{}^\circ -\angle D=2(\angle C+\angle D)\]\[=\text{ }360{}^\circ -\left( \angle C+\angle D \right)=2\left( \angle C+\angle D \right)\] \[\therefore \text{ }360{}^\circ =3\left( \angle C+\angle D \right)\] or \[120{}^\circ =\angle C+\angle D>\angle D+30{}^\circ \] or \[120{}^\circ >\angle D+30{}^\circ \] or \[90{}^\circ >\angle D\] or \[\angle D<90{}^\circ \]
You need to login to perform this action.
You will be redirected in
3 sec
