Question

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Answer 1

Answer:

b. $b.) \frac{\sqrt{2} }{2}$

Step-by-step explanation:

Whenever you are given a question like this

(either triangle has 30-60-90 angles or 45-45-90)

you use the special triangle formula

So since this is a special triangle with 45-45-90 angles

and you are looking for cos 45° (which is $\frac{Adjacent}{Hypotenuse}$ )

1.) Find the Hypotenuse and the Adjacent to cos 45°

$cos=\frac{Adj}{Hypoth} = (\frac{1}{\sqrt{2} } )$

2.) Rationalize the fraction (as it has a radical in the denominator)

$\frac{1}{\sqrt{2} } *(\frac{\sqrt{2} }{\sqrt{2} } )=\frac{\sqrt{2} }{2}$

Answer: frac{\sqrt{2} }{2}[/tex]= Cos (45°)

Answer 2

Answer: B.

Explanation:

Consider any right triangle that has both its legs of same length. In this case both the other two angles would be 45 degrees each. Now, if both its legs are considered of unit length, then hypotenuse would be of length √2.

The cos 45 = 1/√ 2 = √ 2/2

Hope this helped! :)