help me in all these for 50 POINTS

Answer:
C. 5√ 2
7.07106781187
Step-by-step explanation:
Because you want to find the value of x, you must use the Pythagorean theorem: a^2+b^2=c^2
(a and b are the values of the legs and c is the value of the hypotenuse, in other words, the diagonal)
Now, plug in your values:
a=x
b=x
c=10
x^2+x^2=(10)^2
Now, simplify and combine your like terms (terms of the same variables and are raised to the same power):
x^2+x^2=10^2
2x^2=100
Now, solve for x:
2x^2=100 (divide both sides by two to isolate x^2)
÷ 2 ÷2
=
x^2=50 (now, square root both sides to isolate x)
=
This will result in x=.
However, you must simplify this square root in order to get your final answer.
To simplify this root, you must factor into the largest perfect square that is also a factor of the radical. This would be