A)
a•b=20
a=b
a=b=square root from 20
c•d=30
c=d
c=d=square root from 30
a^2+c^2=d^2
20+30=d^2
50=d^2
d=square root from 50
Area=square root from 50•square root from 50=50
B)
a•b=16
a=b
a=b=square root from 16=4
c•d=36
c=d
c=d=square root from 36=6
a^2+c^2=d^2
4^2+6^2=d^2
16+36=d^2
d=square root from 52
Area=square root from 52•square root from 52=52