Question

Foarte urgeeeent:
DETERMINATI PERIMETRUL TRIUNGHIULUI ABC CU MASURA UNGHIULUI B DE 90 GRADE STIING CA:
1.AB=7 CM
COS A-0,28

2.AC=20 MM
SIN C-O,8

3.BC-4 DM
SIN A=O,(97560)

Answer 1

1. cosA=O,28=28/100=cateta alaturata/ipotenuza=AB/AC
28/100=7/AC⇒AC=25 cm 
ΔABC dreptunghic⇒BC²=AC²-AB²⇒BC²=25²-7²=625-49=576⇒BC=24 
P=24+7+25=56 cm
2. AC=20mm=2cm
sin C=o,8=8/10=4/5= cateta opusa/ipotenuza=AB/AC
4/5=AB/2⇒AB=8/5
BC²=AC²-AB²
BC²= 4-64/25=(100-64)/25⇒BC=6/5P=2+6/5+8/5=24/5 cm
 
3. BC=4 dm=40 cm
sinA=97560/99999
sinA=BC/AC
40/AC=97560/99999⇒AC= 40.99999/97560=41 cm
AB²=AC²-CB²=41²-40²=1681-1600=81
AB=9 cm
P= 9+40+41=90 cm