We can see on this graph that the triangle has legs of x and 6 with a hypotenuse of 10 and we can use Pythagoreans theorem to find the unknown side.
Pythagoreans theorem: a^2+b^2=c^2, where a and b are the legs of the triangle and c, is the hypotenuse
x^2+6^2=10^2 Plugin a=x, b=6, and c=10. Now let us solve for x
x^2+36=100 Square each individual term
x^2+=100+36 Subtract 36 from both sides
x^2=64 Combine like terms
sqrt(2)=sqrt(64) Take the square root of both sides
x = 8 Simplify the square root
So our answer is x = 8
The ladder touches the 8 feet mark on the wall.