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Please help me with this Geometry problem, I'm stuck on it :(

Please help me with this Geometry problem, I'm stuck on it :(-example-1
User Danywalls
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1 Answer

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For a given triangle with sides a, b, c and a corresponding angle, A to side a(opposite side a), we would find the measure of the angle by applying the cosine rule which is expressed as

a^2 = b^2 + c^2 - 2bcCosA

Looking at the given triangle, given that a = 12, b = 7, c = 10 and angle A = x, the formula would be applied as shown below

12^2 = 7^2 + 10^2 - 2 * 7 * 10 * Cosx

144 = 49 + 100 - 140Cosx

144 = 149 - 140Cosx

140Cosx = 149 - 144

140Cosx = 5

Cosx = 5/140

Cosx = 0.0357

x = Cos^(- 1)(0.0357)

x = 87.95 degrees

User Jmishra
by
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