Classify the triangle based on the side lengths 4.2, 6.4 and 7.6. right acute obtuse no triangle can be formed with given side lengths

The triangle is acute.

Basically, you need to use Pythagoras Theorem.

This is what you need to know then

In ABC with longest side c:

c²<a²+b² then the triangle is acute.

c²=a²+b² then the triangle is right.

c²>a²+b²  then the triangle is obtuse.

So let´s go Pythagoras Theorem for your triangle.

4.2²=17.64

6.4²=40.96

7.6²=57.76

57.76<17.64+40.96

So the triangle is acute

10 cm

step-by-step explanation:

if the polygon is a rectangle, then the perimeter is x+x+y+y. using the values that you gave, the perimeter is 3+3+2+2=10cm.