Question

Question #1f8eb

Answer 1

I take it that you want to show it's a right angled triangle, therefore we need Pythagoras.

Explanation:

From our sides, we know that the longest side of the triangle is 90 units, therefore, this must be our hypotenuse.

Using Pythagoras `a^2 + b^2=c^2` with c being the hypotenuse
we assume that `80^2 + 10^2 = 90^2`

Therefore to find c, we do `c=sqrt(80^2+10^2)`
where `c = 10sqrt(65)`

As c does not originally equal 90 like we hoped, this triangle unfortunately not right angled.