The distance of the bird from the ground will be given by:
tan θ=opposite/adjacent
θ=50°
opposite=h
adjacent=12 ft
plugging in the values in the formula we get:
tan 50=h/12
thus
h=12tan50
h=14.301 ft
=14.3 ft
Make bottom number same
ok, so remember
(a-b)(a+b)=a²+b²
so
to get from (y-x) to (y²-x²), multiply 2nd fraction by (y+x)
so multiply 2nd fraction by (y+x)/(y+x)

=

=
Using the distributive property, a(b+ c) = ab + ac. In this case, b is 30, so the blank is 30.