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Answer:
If the radius of the circle is 6 cm and AG = 8, then the length of BC is 13.4 cm.
Step-by-step explanation:
Referring to the figure attached below
The radius of the circle, AO = 6 cm
∴ The diameter of the circle, AB = 6*2 = 12 cm
AG = 8 cm
Join points B and G.
Step 1:
We know that the angle subtended by the diameter of the circle on any point of the circle is 90°.
∴ ∠AGB = 90°
Let’s assume ∠GAB = “θ”.
Applying the trigonometry properties of triangles in ∆AGB, we get
cos θ = Base/ hypotenuse=AG/AB
⇒ cos θ = 8/12
⇒ cos θ = 2/3
⇒ θ = cos⁻¹ (0.667)
⇒ θ = 48.16°
Step 2:
We also know that the angle made by the tangent and the radius of the circle is equal to 90°.
∴ ∠BCO = ∠BCA = 90°
Now, consider ∆ABC and apply the trigonometry properties of triangles, we get
tan θ = perpendicular/base= BC/AB
⇒ tan 48.16° = …… [here ∠GAB = ∠CAB = θ = 48.16°]
⇒ BC = 1.116 * 12
⇒ BC = 13.39 cm ≈ 13.4 cm
Thus, the length of BC is 13.4 cm .
Hope it is helpful for you....