answer:7.74cm
explanation:firstly draw figure
in rectangle abcd
dc=ab (as opposite sides of rectangle are equal)
apply pythagoras theorem that is H²=P²+B²
where b is 8 cm h is 2 cm .
(2)²=P²+(8)²
4=P²+64
4-64=P²
-60=P²
square rootof -60 =P
P=7.74
hence AD=7.74cm