Part a
Find out the height of the triangle of the figure
we have that
sin(70)=h/2 -----> by opposite side divided by the hypotenuse
solve for h
h=2*sin(70)
h=1.88 m
Part b
Find the base of complete triangle
so
Let
x-----> the base of complete triangle
we have that
x=2*cos(70)+h/tan(40)
substitute the value of h
x=2*cos(70)+1.88/tan(40)
x=2.92 m