In triangle XYZ, ∠XYZ = 15o, ∠XZY = 45o and lXYl = 7 cm. Find lYZl.
- 14√2 cm
-
\(7\left(\frac{\sqrt{6}}{2}\right)\)
- 7√2 cm
- 7 cm
The correct answer is: B
Explanation
= 180 - 60
= 120o
Using sine rule
\(\frac{x}{sinx}=\frac{7}{sinz}\\
\frac{x}{sin 120}=\frac{7}{sin 45}\\
x=\frac{7 sin 120}{sin45}\\
x=\frac{7sin(180-120)}{sin 45}\\
x=\frac{7 sin 60}{sin 45}=\left(7\left(\frac{\sqrt{3}}{2}\right)\div \frac{1}{\sqrt{2}}\right)\\
x =\left(7\left(\frac{\sqrt{3}}{2}\right)\div \frac{1}{\sqrt{2}}\right)\\
x = 7\left(\frac{\sqrt{6}}{2}\right)\)