cosine angle a!!!!!!!

Question

 

 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

Answer 1

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.