Question

$△$ABC is constructed such that AB = 5 cm, BC = 7 cm and $\angle$B = 50${}^{\circ }$. Then, the measure of $\angle$A is

• A. 45${}^{\circ }$
• B. 85${}^{\circ }$
• C. 50${}^{\circ }$
• D. 76${}^{\circ }$

Answer 1

The correct option is B

85${}^{\circ }$

Step 1:
Draw the base line AB of the length 5 cm.

Step 2:
Measure the angle B with your protractor. Make a mark at 50 degrees and draw a line from B passing through the mark.

Step 3:
Cut an arc of radius 7 cm on the line passing through the point B. The point where this arc cuts the line is the point C.

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

From the above construction, we see that the measure of $\angle$A is 85${}^{\circ }$.