Which of the following is correct about an obtuse angled triangle?

In the given figure, the value of $A{D}^2$ is

How many altitudes does a right-angled triangle have?

Which of the following is possible in a $∆PQR$?

In the adjoining figure, if $x$ is two-third of $z$ then the value of $z$ is

The angle of triangle are in the ratio $3:5:4$. Find the difference between the measures of largest and smallest angles

In a triangle, if one angle is complement of the other, then the triangle is a _____