Please help~Hannah

Alternating angles are =     x = 21 degrees

or the sum of the angles in a triangle = 180  

the other angle near A = 90 - 21 = 69^o

then   69 + x + 90 = 180^o

            x + 159 = 180

             x = 21 degrees

x is an alternate interior angle, so it's the same as 21 degrees. 

21 = 21

Hope this helped :))

=^._.^=