Question

se considera triunghiul cu aria 8 laturile AB 4 BC 8 sa se calculeze masura unghiului B

Answer 1

   
[tex]\displaystyle\\ \text{Se da:}\\ \Delta ABC\\ AB=4\text{ cm}\\ BC = 8\text{ cm}\\ Aria = 8\text{ cm}^2\\ \text{Se cere:}\\ m(\sphericalangle B)= ?\\\\ \text{Rezolvare:}\\\\ Aria = \frac{AB\cdot BC \cdot \sin(B)}{2}=8\\\\ AB\cdot BC \cdot \sin(B)=2\cdot8\\\\ AB\cdot BC \cdot \sin(B)=16\\\\ \sin(B) = \frac{16}{AB\cdot BC} = \frac{16}{4\cdot 8}= \frac{16}{32}=\boxed{\bf \frac{1}{2}}\\\\ \Longrightarrow~~\boxed{\bf m(\sphericalangle B)=30^o} [/tex]

Answer 2

4*8*sinB*1/2=8
4*sinB *1/2=1
2sinB=1
sinB=1/2⇒la gimnaziu,
(cf. valorilor invatate pe de rost pt UNELE unghiuri ascutite)⇒m∡B=30°