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In DeltaABC, with the usual notations, i...

In `DeltaABC`, with the usual notations, if `sinB sinC=(bc)/(a^(2))`, then the triangle is

A

Right angled triangle

B

Obtuse angled triangle

C

Equilateral triangle

D

Acute angled triangle

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The correct Answer is:
To solve the problem, we start with the given equation: \[ \sin B \sin C = \frac{bc}{a^2} \] where \( a, b, c \) are the sides of triangle \( ABC \) opposite to angles \( A, B, C \) respectively. ### Step 1: Rewrite the equation using the Law of Sines From the Law of Sines, we know that: \[ \frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C} \] This implies: \[ \sin B = \frac{b \sin A}{a} \quad \text{and} \quad \sin C = \frac{c \sin A}{a} \] ### Step 2: Substitute \(\sin B\) and \(\sin C\) into the equation Substituting these into the original equation gives: \[ \left(\frac{b \sin A}{a}\right) \left(\frac{c \sin A}{a}\right) = \frac{bc}{a^2} \] ### Step 3: Simplify the left-hand side This simplifies to: \[ \frac{bc \sin^2 A}{a^2} = \frac{bc}{a^2} \] ### Step 4: Cancel \(bc\) from both sides Assuming \(bc \neq 0\) (which is true since they are sides of a triangle), we can cancel \(bc\): \[ \sin^2 A = 1 \] ### Step 5: Solve for \(\sin A\) Taking the square root of both sides, we find: \[ \sin A = 1 \] ### Step 6: Determine the angle \(A\) The only angle for which \(\sin A = 1\) is: \[ A = 90^\circ \] ### Conclusion Since angle \(A\) is \(90^\circ\), triangle \(ABC\) is a right-angled triangle. ### Final Answer The triangle is a right-angled triangle. ---

To solve the problem, we start with the given equation: \[ \sin B \sin C = \frac{bc}{a^2} \] where \( a, b, c \) are the sides of triangle \( ABC \) opposite to angles \( A, B, C \) respectively. ...
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