Question

$△$ABC is constructed such that AB = 3 cm, AC = 7 cm and $\angle$B = 15${}^{\circ }$. Then, the length of the third side is

• A. 4 cm
• B. 5 cm
• C. 7 cm
• D. 9 cm

Answer 1

The correct option is D 9 cm

Step 1:
Draw a line segment of AB of length 3 cm.

Step 2:
Mark a line making an angle 15${}^{\circ }$ at B.

Step 3:
Draw an arc of radius 7 cm with centre at A.

Step 4:
Draw an arc to cut the line from B.

Step 5:
Mark the intersecting point as C.

Step 6:
Join CA to get the required $△$ABC


From the above construction, we see that the length of the third side is 9 cm.