Question

What type of triangle is formed by the side lengths below? 7cm 9cm 11cm A. Acute B. Right C. Obtuse D. Cannot form a triangle

Answer 1

Answer:

A. Acute

Step-by-step explanation:

To start, determine whether you can form a triangle or not. In any triangle, the sum of any two sides must be greater than the third side. In this case, this holds true and we can definitely form a triangle.

Let $c$ be the longest side of the triangle and let $a$ and $b$ be the other two sides.

If $a^2+b^2>c^2$, the triangle is acute.

If $a^2+b^2=c^2$, the triangle is right.

If $a^2+b^2<c^2$, the triangle is obtuse.

Substituting given information:

$7^2+9^2>11^2$, therefore the triangle is acute.