the lengths of the sides of a triangle are 11, 15, and 20 classify the triangle as acute, right, or obtuse.

The given triangle is NOT A RIGHT ANGLED triangle.

Step-by-step explanation:

Here, the given three sides of the triangle are: 11 , 15 and 20.

A. To check if the given triangle is RIGHT ANGLED or NOT

Here, the longest side  = 20

So, he hypotenuse  = 20

Now, if the given triangle a right angled then by PYTHAGORAS THEOREM

This is a CONTRADICTION   as, 400 ≠ 346

Hence the given triangle is NOT A RIGHT ANGLED triangle.

Now, we CAN NOT decide if the triangle is an Acute or Obtuse angled with the help of given sides.

For that classification, ANGLES SHOULD BE KNOWN.