Help with 3 questions please!

1)   tan(x) = opposite/adjacent   so  x = tan^-1(opposite/adjacent)  

      Here we have:  x = tan^-1(5/20)

      You can use the calculator on this site to evaluate this  (note that atan is the same as tan^-1).

 

2)   sin(angle) = opposite/hypotenuse   so   sin(45°) = 4sqrt(2)/x  or  x = 4sqrt(2)/sin(45°)

 

3)  Take the "base" to be the 11cm side.  The "height" is then given by 9*sin(63°) cm  The area is obtained from (1/2)base*height.