Question

need help in finding the area of this triangle

Answer 1

Answer:

अक्षिनिम दीदी करोड़ दीक्षा दुआ

Answer 2

Answer:

2.794 cm²

Step-by-step explanation:

Let us first find ∠A.

∠A + ∠B + ∠C = 180

∠A + 10 + 65 = 180

=> ∠A = 105°.

We know lengths of two sides AB and AC and ∠A is the included angle. We can use SAS (Side-Angle-Side) method,

The area of triangle = AB * AC * SinA/2 = 1.8 * 3.2 * Sin 105°/2.

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To Calculate value of SIn 105° (if not already given in question):

Sin 105° = Sin (90 + 15)° = Cos 15°.

We know that Cos2θ = 2Cos²θ - 1 => Cosθ = √ 1 + Cos2θ/2

Thus Cos 15° = √1 + Cos30/2   = √[1 + (√3/2)] / 2  = 1/2[√(2 + √3)] = 0.97.

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Thus Area of triangle = 1.8 * 3.2 * 0.97/2 = 2.794 cm²