Question

In triangle ABC, sinA= 0.3, sinB=0.4 and a=12. Find b

Answer 1

b = 16

Explanation:

Use the formula of an area of a triangle:

`A=(1)/(2)bc\sin A=(1)/(2)ac\sin B=(1)/(2)ab\sin C`

Therefore we have the equation:

`(1)/(2)bc\sin A=(1)/(2)ac\sin B` multiply both sides by 2

`bc\sin A=ac\sin B` divide both sides by c

`b\sin A=a\sin B` divide both sides by sin A

`b=(a\sin B)/(\sin A)`

We have

`\sin A=0.3,\ \sin B=0.4,\ a=12`

Substitute:

`b=((12)(0.4))/(0.3)=(4.8)/(0.3)=(48)/(3)=16`