Question

If a triangle of sides AB = 3 cm, BC = 7 cm and AC = 5 cm is constructed, then the measure of the angle B is

• A. lies between 20${}^{\circ }$ and 30${}^{\circ }$
• B. lies between 30${}^{\circ }$ and 40${}^{\circ }$
• C. lies between 40${}^{\circ }$ and 50${}^{\circ }$
• D. lies between 50${}^{\circ }$ and 60${}^{\circ }$

Answer 1

The correct option is A lies between 20${}^{\circ }$ and 30${}^{\circ }$

Let us construct the required triangle as follows:

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

Step 2:
Draw an arc of 5 cm by taking A as centre.

Step 4:
Draw an arc of 7 cm by taking B as centre.

Step 3:
Mark the intersecting point as C.

Step 4:
Complete the triangle by drawing the lines between all three points, as shown below.

Now, by above construction we see that the measure of $\angle$B is 27${}^{\circ }$.