Geometric mean of 9 and 30

Alocal concert promoter purchases 2 3/4 pages of ads. when one of the concerts is cancelled, the promoter cancels 1 5/8 pages of ads. how much advertising space is the concert promoter actually using?

What is negative 3/9 times negative 2/8 ?

Ade and abc are similar. which best explains why the slope of the line between points a and d is the same as the slope between points a and b?