A = 360 cm^2
Explanation:
Using Pythagorean theorem, the length AB is given by
AB^2 = 17^2 - 8^2 = 225 cm^2
or
AB = 15 cm
Since the ratio BC: CD = 1:2 and BC = 8 cm, this means that CD = 2×(8 cm) = 16 cm
so the length BD is
BD = BC + CD = 8cm + 16 cm = 24 cm
There the area of the rectangle is
A = AB×BD
= 15cm×24cm
= 360 cm^2