We have the following:
(i)
By cross multiplication, we get:
5 12 = 60 and 7 8 = 56
However, 60 > 56
∴
(ii)
By cross multiplication, we get:
5 15 = 75 and 9 11 = 99
However, 75 < 99
∴
(iii)
By cross multiplication, we get:
11 16 = 176 and 12 15 = 180
However, 176 < 180
∴