Question 410317
You can use the pythagorean theorem.
Let {{{h}}} = vertical height of top of ladder
{{{h^2 + 8^2 = 22^2}}}
{{{h^2 = 22^2 - 8^2}}}
{{{h^2 = 484 - 64}}}
{{{h^2 = 420}}}
{{{h = 20.5}}} ft 
check answer:
{{{8^2 + 20.5^2 = 484.25}}} close enough