first one
we see that since both traignels are having right angles, and same corner angle (BAC) their sides are proportional
we notice that CB=AB so therefor
ED=DA
12=12
but wait, x=AD-AB=12-2=10
x=10
circumference=2pir
2pi=2pir
divide both sides by 2pi
1=r
nice
area=pir^2
area=pi1^2
area=pi1
aera=pi
area=pi units or 3.14 unts