Question

A triangle of sides AB = 4.3 cm, BC = 9.5 cm and AC = 6.4 cm is constructed. Then, $△$ABC is

• A. an acute scalene triangle
• B. an obtuse scalene triangle
• C. a right scalene triangle
• D. an acute isosceles triangle

Answer 1

The correct option is B an obtuse scalene triangle

Let us construct the required triangle as follows:

Step 1:
Draw the base line AB of the length 4.3 cm.

Step 2:
Use your compass to make an arc with centre at point B and the radius 9.5 cm.

Step 3:
Use your compass to make an arc with centre at point A and the radius 6.4 cm.

Step 4:
In the point of intersection between the two arcs, you'll find the point C.
Complete the triangle by drawing the lines between all three points, as shown below.

Now, by above construction we see that the measure of $\angle$A is 123${}^{\circ }$, measure of $\angle$B is 37${}^{\circ }$ and measure of $\angle$C is 20${}^{\circ }$.

Hence, the given triangle is a obtuse-angled scalene triangle.