Question

PLS HELP what is the length of side s of the square shown below ?

Answer 1

Answer:

$\sqrt{2}$ A.

Step-by-step explanation:

There's a few ways you can go about solving this, but the way I would go with is using sine law.

Sine law:

$\frac{sinA}{a} = \frac{sinB}{b}$

in the equation above 'A' an angle, and 'a' would be the length of the side opposite to it. Same thing for B.

You are given the angle 90 degrees, and its opposite side length is 2.

You are also given 45 degrees from one of the corners but it doesn't tell you its side length.

There is one corner where it doesn't tell you the angle but you can figure it out using the law that the angles in a triangle must add up to 180 degrees.

So you subtract the other angles to find the angle of the bottom right angle.

180-90-45 = 45

The reason we want to find that angle, is so we can use sin law to find s.

Write down what you have so far:

$\frac{sin90}{2} = \frac{sin45}{s}$

Now all you need to do is solve for s.

$\frac{sin90*s}{2} = \frac{sin45}{1}$

sin 90 is 1.

$\frac{1*s}{2} = sin45\\ \\s = 2*sin45$

Now since the answers available are in exact values, you can't just punch this in your calculator.

$sin45 = \frac{\sqrt{2} }{2}$

so,

$s = 2*\frac{\sqrt{2} }{2} = \sqrt{2}$