Question 135851
For your first question, you didn't give the side lengths of the triangle, so all I can tell you is that if the measure of the longest side (the hypotenuse) squared is equal to the sum of the other two sides after you square each of them, then it is a right triangle.  Otherwise not.  So if your sides are length a, b, and c, and c is the longest side, if {{{c^2=a^2+b^2}}}, then the triangle is a right triangle.


The height, width, and diagonal of a computer screen make a right triangle.  Using the formula in the first question, you can say:


{{{19^2=12^2+w^2}}} where w is the width.  Rearranging:  {{{w^2=19^2-12^2}}}, so {{{w=sqrt(19^2-12^2)}}}.   Punch that into a calculator and then round off to the nearest inch.