What is the radius of the circle in cm? The rectangle at the corner measures 10 cm  * 20 cm.
The  right bottom corner of the rectangle is also a point on the circumference of the circle.
What is the radius of the circle in cm?
Is the data sufficent to get the radius of circle?


$$r^2=x^2+y^2 \tag{1}$$
$r=y+20$ and $r=x+10$ therefore 
$$y+20=x+10 \quad \mbox{then } \quad y=x-10 \tag{2}$$
Substitute $(2)$ into $(1)$
$$(r+10)^2=x^2+(x-10)^2$$
$$x^2+20x+100=x^2+x^2-20x+100$$
$$X^2=40x$$
$$x=40$$
Then substitute $x=40$ into $(2)$
$$y=40-10$$
$$y=30$$
substitute $x=40$ and $Y=30$ into $(1)$
$$r^2=(40)^2+(30)^2$$
$$r=50\rm{cm}.$$
