Question

The lengths of the sides of a triangle are 9​, 12​, and 18. Classify the triangle as​ acute, right, or obtuse.

Answer 1

Explanation:

Use Pythagorean theorem.

Assign the largest value to 'c'

If a² + b² = c² , then it is right triangle

If a² + b² > c², then it si acute triangle

If a² + b² < c² , then it is obtuse triangle

Here, a = 9 , b = 12 & c = 18

a² + b² = 9² + 12²

= 81 + 144

a² + b² = 225

c² = 18²

c² = 324

a² + b² < c²

225 < 324

So, 9, 12 , 18 form a obtuse triangle