That is 62x9 which is 9x2=18 and 9x60=540 so you then add 540+18=558 chairs
Step-by-step explanation:
horizontal lines will have a gradient(m) of 0
so if m=0 , the line is horizontal
formula to find m:
m=y2-y1 / x2-x1
insert coordinates into formula

As m=0 , therefore it is a horizonta line.
hope this helps..
K = 4pq^2
k/4p = q^2
0.5(k/p)^1/2 = q