7).

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Step 1 :

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In $\"\"$ , $\"\"$ .

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Law of cosines for $\"\"$ : $\"\"$ .

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Substitute the values $\"\"$ in above equation.

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$\"\"$

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$\"\"$

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Step 2 :

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Law of cosines for $\"\"$ : $\"\"$ .

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Substitute corresponding values.

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$\"\"$

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$\"\"$

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$\"\"$ .

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Step 3:

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Sum of the angles of a traingle is $\"image\"$ .

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$\"\"$

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$\"\"$

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Solution:

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$\"\"$ , $\"\"$ and $\"\"$ .

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8).

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Step 1 :

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In $\"\"$ , $\"\"$ and $\"\"$ .

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Sum of the angles of a triangle is $\"image\"$ .

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$\"\"$

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Step 2 :

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Law of sines : $\"image\"$

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Consider $\"\"$ .

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Substitute $\"\"$ , and $\"\"$ in above expression.

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$\"\"$

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step 3 :

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Consider $\"image\"$ .

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Substitute corresponding values in above equation.

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$\"\"$

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Solution:

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$\"\"$ , $\"\"$ , and $\"\"$ .

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