We have a right triangle, in order to find the missing sides we will use trigonometric functions
we will use the function tangent to find b
[tex]\tan (40)=\frac{b}{20}[/tex]we need to isolate the b
[tex]\begin{gathered} b=\tan (40)\cdot20 \\ b=16.78 \end{gathered}[/tex]b round to the nearest tenth is b=16.8
For c we will use the cosine
[tex]\cos (40)=\frac{20}{c}[/tex]we need to isolate the c
[tex]c=\frac{20}{\cos (40)}=26.1[/tex]round to the nearest tenth c=26.1
then to find angle A we need to remember that the sum of the interior angles of a triangle is 180°, so the equation to find A is
40+90+A=180
A=180-90-40
A=50°