The given question describes a right triangle with the hypotenuse as 10 ft and one of the legs as 6 ft.
We can make use of Pythagoras theorem to evaluate the length of the other side.
We know that by Pythagoras theorem, the square root of the sum of the squares of the legs of a right triangle gives the hypotenuse. Let the length of the required leg be x, then
[tex] x^2+6^2=10^2\\ \\ \Rightarrow x^2=100-36=64\\ \\ \Rightarrow x=\sqrt{64}=8. [/tex]
Therefore, the ladder reached 8 ft high on the building.
