Question

Ex 15,16,17 si 18. Rezolvare completa. Este urgent! Va rog

Answer 1

15. 4dm=40 cm
41²=40²+a², a²=41²-40²=(41-40)(41+40)=81, a=9
P=2(40+9)=98
A=40x9=360
16. 3 dm=30 cm
l²=8²+15²=64+225=289, l=17
17. 60+60+2x=360, x=120°
ΔABC t cosinusului
AC²=AB²+BC²-2ABxBCcos120
cos120=cos(180-60)=-cos60
AC²=36+64+6x8x1/2=100+24=124, AC=2√31
ΔABD t cosinusului
DB²=AD²+AB²-2ADxABcos60=100-6x8x1/2=100-24=76, DB=2√19
18. BC²=12²+5²=144+25=163, BC=13
P=12+15+13+10=50
t lui Pitagora in ΔADC
AC²=10²+12²=100+144=244, AC=2√61
ΔABD t lui Pitagora
BD²=AD²+AB²=144+225=369, BD=3√41