Question

In a triangle ABC, sinA : sinB : sinC = 1 : 2 : 3. If b = 4 cm, then the perimeter of the triangle is -

• A. 6 cm
• B. 24 cm
• C. 12 cm
• D. 8 cm

Answer 1

Answer: (C)

12 cm

According to sin rule: $\frac{a}{\sin A}=\frac{b}{\sin B}=\frac{c}{\sin C}$

$⟹a$$=4\times \frac{\sin A}{\sin B},c=4\times \frac{\sin C}{\sin B}=4\times \frac{1}{2}=2cmc=4\times \frac{3}{2}=6cm$

$perimeter=a+b+c=2+4+6=12cm$