If $P (0,0), Q (0,5)$ and $R (6,0),$ then $\Delta PQR$ is $\ldots \ldots \ldots$ triangle.

The distance between the points $A(a+b, b-a)$ and $B(a-b, a+b)$ is............

If $(-8, -4), (-2, 4)$ and $(5, a)$ are collinear points,then find the value of $a$.

The end points of the diameter of a circle are $(2, 4)$ and $(2, 6)$. The radius of the circle is:

Ayush starts walking from his house to his office. Instead of going to the office directly,he goes to a bank first,from there to his daughter's school,and then reaches the office. What is the extra distance travelled by Ayush in reaching his office (in $, km$)? (Assume that all distances covered are in straight lines).
If the house is situated at $(2,4)$,the bank at $(5,8)$,the school at $(13,14)$,and the office at $(13,26)$,where coordinates are in $km$.

Using the distance formula,show that the points $A(7,3)$,$B(3,0)$,$C(0,-4)$,and $D(4,-1)$ are the vertices of a rhombus.