Question

$△$ABC is constructed such that AB = 7 cm, AC = 4 cm and $\angle$A = 75${}^{\circ }$. Then the length of side BC is _____ .

• A. 6.8 cm
• B. 7.1 cm
• C. 7.4 cm
• D. 7.7 cm

Answer 1

The correct option is B

7.1 cm

Step 1:
Draw the base line AB of the length 7 cm.

Step 2:
Measure the angle A with your protractor. Make a mark at 75 degrees and draw a line from A passing through the mark.

Step 3:
Cut an arc of radius 4 cm on the line passing through the point A. The point where this arc cuts the line is the point C.

Step 4:
Draw a line from B to point C to get the required triangle ABC, as shown below.

From the above construction, we see that length of side BC is 7.1 cm.