Classify the object with the given side lengths as acute, obtuse, right, or not a triangle. 16, 21, 28
Right
Acute
Obtuse
Not a triangle

We have to first see that the given lengths makes a triangle or not by using a+b > c in which a,b and c are

length of sides of a triangle lets check out

16 + 21 = 37 > 28

21 + 28 = 49 > 16

16+ 28 = 44 > 21

As because the statement fits correct in the lengths given so its a triangle

So we can say that the triangle is scalene by means of measurements

but cant be a right angle as by taking the pythagorean triplet

= a^2 + b ^ 2 = c^2

lets see if a=16, b = 21 and c = 28

So a^2 + b^2

= 256 + 441

= 697

but c^2

= 28^2 = 784

As 441 =/= 784

So The triangle lengths cant be a right angled triangle

So 1/2 of possibility is the traingle acute and 1/2 of the possibilty that the triangle is obtuse

Now you can find the correct triangle on the basis of acute or obtuse angle by drawing with given length of sides of triangle

Hope it helps