Question

In which of the following conditions the sine rule can be used ?

• A.
  When all the 3 angles are given
• B.
  When all the 3 sides are given
• C.
  When 2 sides and a non including angle is given
• D.
  When 2 angles and a non including side is given

Answer 1

Answer: (C), (D)

The correct options are
C
When 2 sides and a non including angle is given
D

When 2 angles and a non including side is given
The sine rule formula is given as$\frac{a}{\mathrm{Sin}A}=\frac{b}{\mathrm{Sin}B}=\frac{c}{\mathrm{Sin}C}=2R$

So to calculate the unknown values, we should have atleast 1 ratio. For eg. in $\frac{a}{\mathrm{Sin}A}$ , we have values of both 'a' and 'Sin A' and therefore, we can calculate all the other unknowns.