The given info is sufficient to warrant the conclusion that both triangles are 45-45-90 triangles.
The measure of angle B is 45 degrees, or pi/4 radians.
The cosine of this angle B is 1/√2, or √(2)/2. This is approx. 0.707.
There is a way to do this algebraically using equations, but it is really messy so I am going to go over the way to do it. The way you do this is by finding whole numbers that multiply to make -192. Start with 1 and 192, 2 and 96, 3 and 64, etc and make the smaller number negative.
The reason why you make the smaller number negative is because we are looking for what numbers add together to make a positive number (10). If the bigger number was negative, then we would get a negative sum.
From what i could find, there aren't any whole numbers that satisfy this, and i doubt that the question would want you to find decimals for this.
The way to find this with equations (in short) is to have to variables, x and y, and make two equations. in this case x+y=10 and xy=-192. Solve one equation for a variable and then use substitution to plug that variable into the other equation. if you do this you get really long decimals.
13) A.
14) D.
15) D.
16) B.
17) A.
