Figura to trójkąt prostokąty więc skorzystamy z twierdzenia pitagorasa: $x^2+y^2=c^2$ czyli

a)

$c^2=8^2+9^2\Rightarrow c^2=64+81=145\Rightarrow a=c=\sqrt{145}\approx 12cm$ $c^2=8^2+9^2\Rightarrow c^2=64+81=145\Rightarrow a=c=\sqrt{145}\approx 12cm$

b)

$b^2=2^2-1^2\Rightarrow b^2=4-1=3\Rightarrow b=\sqrt{3}\approx 173cm$

c)

$c^2={\left(2,5\right)}^2-{\left(0,7\right)}^2\Rightarrow c^2=6,25-0,49=5,76\Rightarrow c=2,4=240cm$

d)

$d^2={\left(22\right)}^2+{\left(16\right)}^2\Rightarrow d^2=484+256\Rightarrow d=\sqrt{740}\approx 27cm$