ElectricPavlov

The first one is  'C'    where    sinx = + sqrt2/2   is in 1 st and 2 nd quadrants      pi/4 and 3pi/4

The second one is  'D'     at pi/7   and 6pi/ 7   sin has the same positive value. 

(Sin is negative from pi to 2pi....thought the question only asked about 0-->pi )

\(\sqrt{}\)\(\Pi \)  =   sqrt(3.14)  = 1.7725

Remember   SOHCAHTOA       Tangent = sin / cos

Tan a  = 1 = sin a / cos a  

or  cos a = sin a

the only value where sina = cosa  = +- sqrt(2)/2

Not sure why info is given about tan b

3.16 x 10^(-23)  x  10^9   =   3.16 x 10^(-23+9)  =  3.16 x 10^(-14)

Equation of a line is   y= mx + b    Where 'm' = slope     and  'b' = y-axis intercept (where x = 0)

First find slope    

m = rise/run  = ( y1-y2 ) / ( x1-x2)

m= (3.1-2.2)/ (28-10) = .9/18 = .05

So   y = .05 x + b      Use ONE of the ordered pairs to calculate 'b'

       3.1 = .05(28) + b    yields b = 1.7

So y = .05x + 1.7     is the line equation.   

3/4 x 1 75/100

=3/4 x 1 3/4

=3/4 x 7/4 = 21/16

3/4  x  1  75/100

= 3/4 x 1  3/4

=3/4 x 7/4 =  21/16

546875 / 1000000   =  35/64

Between 9 and 10

    9^2 = 81   10^2 = 100

     sqrt(90) = 9.486

650 x 10^9   is 650 billion    650,000,000,000