Question

Given below are the steps for the construction of a quadrilateral ABCD, where AB = 3.5 cm, BC = 6.5 cm, $\angle A={75}^{\circ },\angle B={105}^{\circ }$ and $\angle C={120}^{\circ }$. Which of the following is wrong?
1:- Draw AB = 3.5 cm.
2:- Construct $\angle DAB={75}^{\circ },\angle ABC={105}^{\circ }$ at B.
3:- Draw BC = 6.5 cm.
4:- At D construct $\angle ADC={120}^{\circ }$.

• A. 3
• B. 2
• C. 4
• D. 1

Answer 1

The correct option is C

4

Step 4 is wrong.
Sum of all angles of a quadrilateral is ${360}^{\circ }$. $\angle A$,$\angle B$ and $\angle C$ add upto ${300}^{\circ }$. Thus the value of $\angle D$ should be ${60}^{\circ }$ and not ${120}^{\circ }$ and hence its wrong.