<img src="https://tex.z-dn.net/?f=x%3D-2%5C%5Cx%2B3y%3D4" id="TexFormula1" title="x=-2\\x+3y=4" alt="x=-2\\x+3y=4" align="absmid

$A+B=90^o\to B=90^o-A\\\\\cos B=\cos(90^o-A)=\cos90^o\cos A+\sin90^o\sin A\\\\=\cos A+1\cdot\dfrac{3}{5}=0+\dfrac{3}{5}=\dfrac{3}{5}\\\\\boxed{\cos B=\dfrac{3}{5}}$

$Used:\\\\\cos(x+y)=\cos x\cos y+\sin x\sin y\\\\\cos90^o=0,\ sin90^o=1$

Other method:

Look at the picture.

$\sin\theta=\dfrac{opposite}{hypotenuse}\\\\\sin A=\dfrac{3}{5}\to opposite=3\ and\ hypotenuse=5$

$\cos\theta=\dfrac{adjacent}{hypotenuse}\\\\adjacent=3\ and\ hypotenuse=5\to\cos B=\dfrac{3}{5}$

8 0

3 years ago

A 90° angle is divided into 2 angles.

Lemur [1.5K]

Answer:

this angle's sum is 90°

(3x+40)°+(4x-6)=90°

7x+34=90°

7x=90-34

7x=56

x=56/7

x=8

3x+40 = 3×8+40 = 64°

4x-6 = 4×8-6 = 26°

8 0

3 years ago

The dot plot below shows the hourly rate of some babysitters:

elena55 [62]

3 bhhhh maki cash men un r so if en jus kookie

7 0

3 years ago

Read 2 more answers

What is X<br><img src="https://tex.z-dn.net/?f=%20-%203x%20%2B%2012%20%3D%2021" id="TexFormula1" title=" - 3x + 12 = 21" alt=" -

Paraphin [41]

You would move all terms that don’t contain x to the right side and solve. Answer : x= -3

8 0

4 years ago

Read 2 more answers