Answer:
option 2nd is correct.
Explanation:
We have been given a right angled triangle having right angle at B.
So, we can use pythagoras theorem which is:
(1)
hypotenuse is the longest side.
which is 10 here,.
And x and y are other two sides
Substituting the values in formula in (1) we get:
![10^2=x^2+y^2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/gl5884sejue7ne09f28bfhiclaw37qguf0.png)
![100=x^2+y^2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7ezac9dudslsv4z5g9pz0gn9ylqh2p0ezh.png)
![\Rightarrow √(100-y^2)=x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ofs6h1dvqgfy7qf4imqs0npid853mmfpdv.png)
Therefore, option 2nd is correct.