Question

Помогите плиз №467 и 473

Answer 1

467
R=1/2*AC=1/2*√(AB²+BC²)=1/2*√(16+9)=1/2*√25=1/2*5=5/2
Sш=4πR²=4π*25/4=25π
473
KD=(AD-BC)/2=(8-2)/2=3
AB=CD=KD/tg<D=3:1/2=6
<A=<D
BD²=AB²+AD²-2AB*AD*cosA=36+64-2*6*8*1/2=100-48=52
BD=2√13
S(ABD)=1/2*AB*AD*sinA=1/2*6*8*√3/2=12√3
R=AB*AD*BD/4S=6*4√13*8/4*12√3=4√39/3
S=4πR²=4π*16*39/9=2496π/9=277 1/3π