<span>200 chairs on 40 rows _ 5__ in each row
200/40 =5</span>
2 times 2.5 times 1.5 times 10 equals to 75 square meters.
Q4, 4y²=60
y=√15 ( i am not sure)
q6, (5+y) ²=81
5+y=9
y=4
q7 (x+4) (x) =77
x²+4x-77=0
(x+11) (x-7) =0
x=-11(rej) or x=7
therefore ,length= 7+4=11cm
breadth=7cm