Answer:
The correct answer is 4√3
Step-by-step explanation:
Consider the triangle ABC.
BC = 12 units. ∠ B = 90°. Let ∠ C = α°.
Now let us consider the triangle BDC.
DC = 4 units. ∠ D = 90°. Let ∠ C = α°.
We find here the angle C is common between both the triangles.
∴ For ΔABC, cos α° = [tex]\frac{BC}{AC}[/tex] = [tex]\frac{BC}{12}[/tex]
and for Δ BDC, cos α° = [tex]\frac{DC}{BC} = \frac{4}{BC}[/tex]
Now equating both the equations we get,
[tex]BC^{2}[/tex] = 48
⇒ BC = 4√3
The length of BC is 4√3 units.
