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cosine angle a!!!!!!!

+3 votes

 

 In a right triangle the side opposite angle a is 7 and the side adjacent angle a is 7. What is the cosine of angle a?
A) 1
B) 0.5
C) Sqrt 2/2
D) Sqrt 3/2
asked Feb 16, 2013 in TRIGONOMETRY by angel12 Scholar

1 Answer

+3 votes

Cos(a): adjacent leg/ hypotenuse.

Pythagorean Theorem: hypotenuse = √[(side opposite)2 + (side adjacent)2]

hypotenuse = √[72 + 72] = √[49+49] = √[2(49)] = √[72(2)] = 7√2.

cos(a) = 7/7√2 = 1/√2

Multiply nominator and denominator by √2

cos(a) = √2 / (√2)(√2) = √2/2.

Option C is right choice.

answered Feb 16, 2013 by richardson Scholar

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