K17

a)
75^2+18^2=x^2
x^2=5949
x=77{,}129...\approx77{,}1cm
b)
85^2+22^2=x^2
7709=x^2
x=87{,}8009...\approx87{,}8cm
c)
82^2+16^2=x^2
x^2=6980
x=83{,}546...\approx83{,}5cm